update,

_poc/helloworld.cpp

@@ -0,0 +1,45 @@
+#include <iostream>
+using namespace std;
+
+int main() {
+    // Prompt the user to enter their name
+    cout << "Please enter your name: ";
+    string name;
+    cin >> name;
+
+    // Prompt the user to enter their math, Chinese, and English marks
+    float mathMark, chineseMark, englishMark;
+    cout << "Please enter your math mark: ";
+    cin >> mathMark;
+    cout << "Please enter your Chinese mark: ";
+    cin >> chineseMark;
+    cout << "Please enter your English mark: ";
+    cin >> englishMark;
+
+    // Calculate the average mark
+    float averageMark = (mathMark + chineseMark + englishMark) / 3;
+
+    // Determine the grade based on the average mark
+    char grade;
+    if (averageMark >= 90) {
+        grade = 'A';
+    } else if (averageMark >= 80) {
+        grade = 'B';
+    } else if (averageMark >= 70) {
+        grade = 'C';
+    } else if (averageMark >= 60) {
+        grade = 'D';
+    } else {
+        grade = 'F';
+    }
+
+    // Print the results
+    cout << endl << "Name: " << name;
+    cout << endl << "Math Mark: " << mathMark;
+    cout << endl << "Chinese Mark: " << chineseMark;
+    cout << endl << "English Mark: " << englishMark;
+    cout << endl << "Average Mark: " << averageMark;
+    cout << endl << "Grade: " << grade << endl;
+
+    return 0;
+}

_prompts/helloworld copy.md

@@ -0,0 +1,7 @@
+write some cpp functions:
+
+This system collects student details like name, marks in each subject.
+The system can calculates the overall grade of each student.
+User can add, edit and delete the record to the system manually or upload a file.
+The system should have a counter to check how many records are update on each time.
+User can generate report and the report should be able to download.

_prompts/helloworld.md

@@ -0,0 +1,25 @@
+write some cpp functions:
+
+1. collects student details like name, marks in each subject.
+
+using cpp, write a console program that accepts user input name, maths marks, chinese marks, english marks and grade,
+print them out when the user input done
+
+
+
+
+The system can calculates the overall grade of each student.
+User can
+  add,
+  edit and
+  delete the record to the
+  system manually or
+
+  upload a file.
+  add,
+  edit and
+  delete
+
+
+The system should have a counter to check how many records are update on each time.
+User can generate report and the report should be able to download.

_prompts/step1/step1.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <string>
+
+struct Student {
+    std::string name;
+    int maths_marks, chinese_marks, english_marks;
+    char grade;
+};
+
+int main() {
+    while (true) {
+        Student student;
+        std::cout << "Enter name (or 'END' to quit): ";
+        std::cin >> student.name;
+
+        if (student.name == "END") {
+            break;
+        }
+
+        std::cout << "Enter maths marks: ";
+        std::cin >> student.maths_marks;
+
+        std::cout << "Enter chinese marks: ";
+        std::cin >> student.chinese_marks;
+
+        std::cout << "Enter english marks: ";
+        std::cin >> student.english_marks;
+
+        std::cout << "Enter grade: ";
+        std::cin >> student.grade;
+
+        std::cout << "\nStudent details:\n";
+        std::cout << "Name: " << student.name << "\n";
+        std::cout << "Maths marks: " << student.maths_marks << "\n";
+        std::cout << "Chinese marks: " << student.chinese_marks << "\n";
+        std::cout << "English marks: " << student.english_marks << "\n";
+        std::cout << "Grade: " << student.grade << "\n";
+    }
+
+    return 0;
+}

_prompts/step1/step1.md

@@ -0,0 +1,17 @@
+write a cpp function:
+
+This system collects student details like name, marks in each subject.
+
+using cpp, write a console program:
+that accepts user input
+  - name,
+  - maths marks,
+  - chinese marks,
+  - english marks and
+  - grade,
+
+loop until user enter "END" as name input
+print them out when the user input done
+
+
+

_prompts/step2/prompt.md

@@ -0,0 +1,40 @@
+write some cpp functions:
+
+```
+Add marks record
+Delete marks record
+Edit marks record
+Print current marks record in system
+
+press E to exit
+```
+
+if the user entered 1, the run `functionAdd` so on and forth
+
+```cpp
+#include <iostream>
+
+void print_menu() {
+    std::cout << "Mark Record System\n";
+    std::cout << "-----------------\n";
+    std::cout << "1. Add marks record\n";
+    std::cout << "2. Delete marks record\n";
+    std::cout << "3. Edit marks record\n";
+    std::cout << "4. Print current marks record in system\n";
+    std::cout << "E. Exit\n";
+    std::cout << "Enter your choice: ";
+}
+```
+
+write a cpp function that print the above menu
+
+The system can calculates the overall grade of each student.
+User can add, edit and delete the record to the system manually or upload a file.
+The system should have a counter to check how many records are update on each time.
+User can generate report and the report should be able to download.
+
+using cpp, write a console program that accepts user input name, maths marks, chinese marks, english marks and grade,
+print them out when the user input done
+
+
+

_prompts/step2/test.cpp

@@ -0,0 +1,106 @@
+#include <iostream>
+#include <vector>
+#include <string>
+
+struct MarksRecord {
+    std::string name;
+    int maths_marks, chinese_marks, english_marks;
+};
+
+std::vector<MarksRecord> records;
+
+void print_menu() {
+    std::cout << "Mark Record System\n";
+    std::cout << "-----------------\n";
+    std::cout << "1. Add marks record\n";
+    std::cout << "2. Delete marks record\n";
+    std::cout << "3. Edit marks record\n";
+    std::cout << "4. Print current marks record in system\n";
+    std::cout << "E. Exit\n";
+    std::cout << "Enter your choice: ";
+}
+
+void functionAdd() {
+    MarksRecord record;
+    std::cout << "Enter name: ";
+    std::cin >> record.name;
+    std::cout << "Enter maths marks: ";
+    std::cin >> record.maths_marks;
+    std::cout << "Enter chinese marks: ";
+    std::cin >> record.chinese_marks;
+    std::cout << "Enter english marks: ";
+    std::cin >> record.english_marks;
+    records.push_back(record);
+}
+
+void functionDelete() {
+    std::string name;
+    std::cout << "Enter name to delete: ";
+    std::cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            records.erase(records.begin() + i);
+            break;
+        }
+    }
+}
+
+void functionEdit() {
+    std::string name;
+    std::cout << "Enter name to edit: ";
+    std::cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            std::cout << "Enter new maths marks: ";
+            std::cin >> records[i].maths_marks;
+            std::cout << "Enter new chinese marks: ";
+            std::cin >> records[i].chinese_marks;
+            std::cout << "Enter new english marks: ";
+            std::cin >> records[i].english_marks;
+            break;
+        }
+    }
+}
+
+
+void functionPrint() {
+    for (const auto& record : records) {
+        std::cout << "Name  Maths     Chinese     English     Grade " << "\n";
+        std::cout << record.name << "   "
+          << record.maths_marks << "   "
+          << record.chinese_marks << "   "
+          << record.english_marks << "   "
+          << "\n";
+        std::cout << "\n";
+    }
+}
+
+int main() {
+    char choice;
+    while (true) {
+        print_menu();
+        std::cin >> choice;
+
+        switch (choice) {
+            case '1':
+                functionAdd();
+                break;
+            case '2':
+                functionDelete();
+                break;
+            case '3':
+                functionEdit();
+                break;
+            case '4':
+                functionPrint();
+                break;
+            case 'E':
+            case 'e':
+                return 0;
+            default:
+                std::cout << "Invalid choice. Please try again.\n";
+        }
+    }
+
+    return 0;
+}

_prompts/step3/prompt.md

@@ -0,0 +1,16 @@
+write some cpp functions:
+
+- User can add, edit and delete the record to the system manually or upload a file.
+
+using cpp, write a console program that accepts:
+  user input a csv file path
+
+the program then parse the inputted csv file and insert the record
+
+```
+name,maths,chinese,english
+apple,99,98,99
+banana,99,98,99
+```
+
+

_prompts/step3/test.txt

@@ -0,0 +1,3 @@
+burger 15
+fries 11
+ice-cream 9

_prompts/step3/write_file.cpp

@@ -0,0 +1,45 @@
+#include <iostream>
+#include <fstream>
+#include <iomanip>
+#include <string>
+
+using namespace std;
+
+int main(){
+    //Declare variables
+    ifstream inFile;
+    ofstream outFile;
+    string burger_name, fries_name, icecream_name;
+    int burger_price, fries_price, icecream_price;
+    //Open the input file and output file
+    inFile.open("price.txt");
+
+    if (!inFile) {
+        cout << "Cannot open the input file."
+        << "The program terminates." << endl;
+        return 1;
+    }
+
+    outFile.open("price_output.out");
+    cout << "Processing data" << endl;
+
+    //Read file word by word
+    inFile >> burger_name >> burger_price;
+    inFile >> fries_name >> fries_price;
+    inFile >> icecream_name >> icecream_price;
+
+    //Output file
+    outFile << "The price of " << burger_name
+        << " is $" << burger_price <<"." << endl;
+
+    outFile << "The price of " << fries_name
+        << " is $" << fries_price << "." << endl;
+
+    outFile << "The price of " << icecream_name
+        << " is $" << icecream_price << "." << endl;
+    inFile.close(); // .close(): close a file
+    outFile.close();
+    cout << "Processing completed" << endl;
+
+    return 0;
+}

_prompts/step4.md

@@ -0,0 +1,13 @@
+write some cpp functions:
+
+This system collects student details like name, marks in each subject.
+The system can calculates the overall grade of each student.
+User can add, edit and delete the record to the system manually or upload a file.
+The system should have a counter to check how many records are update on each time.
+User can generate report and the report should be able to download.
+
+using cpp, write a console program that accepts user input name, maths marks, chinese marks, english marks and grade,
+print them out when the user input done
+
+
+

_prompts/step5.md

@@ -0,0 +1,13 @@
+write some cpp functions:
+
+This system collects student details like name, marks in each subject.
+The system can calculates the overall grade of each student.
+User can add, edit and delete the record to the system manually or upload a file.
+The system should have a counter to check how many records are update on each time.
+User can generate report and the report should be able to download.
+
+using cpp, write a console program that accepts user input name, maths marks, chinese marks, english marks and grade,
+print them out when the user input done
+
+
+

gitUpdate.bat

@@ -0,0 +1,7 @@
+git status .
+
+@pause
+
+git add .
+git commit -m"update marissa.sam,"
+start git push

meta.md

@@ -0,0 +1,27 @@
+---
+tags: [cpp, console]
+---
+
+# marissa.sam
+
+Topic 1 Student Report Management System
+
+This system collects student details like
+
+- [ ] name,
+- [ ] marks in each subject.
+  - [ ] maths
+  - [ ] chinese
+  - [ ] english
+  - [ ] grade
+
+The system can calculates the overall grade of each student.
+
+User can add, edit and delete the record to the system manually or upload a file.
+
+The system should have a counter to check how many records are update on each time.
+
+User can generate report and the report should be able to download.
+
+2-4 additional features are required.
+Topic 1 Suggested Records

package.json

@@ -0,0 +1,13 @@
+{
+  "name": "sunny9898",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "gitUpdate": "git add . && git commit -m\"update marissa.sam,\""
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}

task1/NOTES.md

@@ -0,0 +1,27 @@
+Topic 1 Student Report Management System
+
+i. This system collects student details like name, marks in each subject.
+  - HKD 0
+
+ii. The system can calculates the overall grade of each student.
+  - HKD 100
+
+iii. User can add, edit and delete the record to the system manually or upload a file.
+  - HKD 200
+
+iv. The system should have a counter to check how many records are update on each time.
+  - commit button ?
+  - HKD 150
+
+v. User can generate report and the report should be able to download.
+  - HKD 150
+
+vi. 2-4 additional features are required.
+  - Find highest and lowest marks for each subject (who & marks)
+  - Find average marks for each subject (highest and lowest, who & marks)
+  - HKD 300
+
+
+
+https://www.onlinegdb.com/online_c++_compiler
+

task1/_ref/Chapter02/helloworld.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+#include <iomanip>
+
+using namespace std;
+
+int main()
+{
+    std::cout << "Price list of a restaurant"<<endl;
+    std::cout << setw(20)
+        << setfill(' ')
+        << left
+        << "Cheese burger: "
+        << " $"
+        << setw(4)
+        << setfill(' ')
+        << right
+        << "14"
+        << endl;
+}

task1/_ref/Chapter03/helloworld.cpp

@@ -0,0 +1,45 @@
+#include <iostream>
+#include <fstream>
+#include <iomanip>
+#include <string>
+
+using namespace std;
+
+int main(){
+    //Declare variables
+    ifstream inFile;
+    ofstream outFile;
+    string burger_name, fries_name, icecream_name;
+    int burger_price, fries_price, icecream_price;
+    //Open the input file and output file
+    inFile.open("price.txt");
+
+    if (!inFile) {
+        cout << "Cannot open the input file."
+        << "The program terminates." << endl;
+        return 1;
+    }
+
+    outFile.open("price_output.out");
+    cout << "Processing data" << endl;
+
+    //Read file word by word
+    inFile >> burger_name >> burger_price;
+    inFile >> fries_name >> fries_price;
+    inFile >> icecream_name >> icecream_price;
+
+    //Output file
+    outFile << "The price of " << burger_name
+        << " is $" << burger_price <<"." << endl;
+
+    outFile << "The price of " << fries_name
+        << " is $" << fries_price << "." << endl;
+
+    outFile << "The price of " << icecream_name
+        << " is $" << icecream_price << "." << endl;
+    inFile.close(); // .close(): close a file
+    outFile.close();
+    cout << "Processing completed" << endl;
+
+    return 0;
+}

task1/_ref/Chapter03/price.txt

@@ -0,0 +1,3 @@
+burger 15
+fries 11
+ice-cream 9

task1/src - Copy/main copy.cpp

@@ -0,0 +1,297 @@
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+struct MarksRecord {
+    string name;
+    int maths_marks, chinese_marks, english_marks;
+    string grade;
+};
+
+vector<MarksRecord> records;
+
+string functionGetGrade(int maths_marks, int chinese_marks, int english_marks){
+    string grade;
+    int marks_sum;
+    float marks_avg;
+
+    marks_sum = 1;
+    marks_sum = (maths_marks + chinese_marks + english_marks);
+    marks_avg = marks_sum / 3;
+
+    if (marks_avg > 90)  return "A";
+    if (marks_avg > 80)  return "B";
+    if (marks_avg > 70)  return "C";
+    return "D";
+}
+
+void print_menu() {
+    cout << "\n";
+    cout << "Mark Record System\n";
+    cout << "\n";
+    cout << "------------------------------------------\n";
+    cout << "1. Add marks record                       \n";
+    cout << "2. Delete marks record                    \n";
+    cout << "3. Edit marks record                      \n";
+    cout << "4. Print current marks record in system   \n";
+    cout << "5. import records from file               \n";
+    cout << "6. export records to file                 \n";
+    cout << "------------------------------------------\n";
+    cout << "E. Exit\n";
+    cout << "Enter your choice: ";
+}
+
+void functionAdd() {
+    string temp;
+    bool name_pass;
+    name_pass = false;
+
+    MarksRecord record;
+
+    while (!name_pass){
+        bool error;
+        error = false;
+
+        cout << "Enter name: ";
+        cin >> temp;
+
+        for (size_t i = 0; i < records.size(); i++) {
+            if (records[i].name == temp) {
+                error = true;
+                cout << "ERROR: duplicated student name found"<<"\n";
+            }
+        }
+
+        // check if name entered is empty
+        if (temp == string()){
+            error = true;
+        }
+
+        if (!error) {
+            record.name = temp;
+            name_pass = true;
+        }
+    }
+
+    cout << "Enter maths marks: ";
+    cin >> record.maths_marks;
+    cout << "Enter chinese marks: ";
+    cin >> record.chinese_marks;
+    cout << "Enter english marks: ";
+    cin >> record.english_marks;
+    records.push_back(record);
+}
+
+void functionDelete() {
+    string name;
+    bool user_found;
+    user_found = false;
+
+    cout << "Enter name to delete: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            records.erase(records.begin() + i);
+            user_found = true;
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "ERROR: student record not found";
+    }else{
+        cout << "1 record deleted.";
+    }
+}
+
+void functionEdit() {
+    string name;
+    string temp;
+    bool user_found;
+
+    cout << "Enter name to edit: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            user_found = true;
+            cout << "Enter new maths marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].maths_marks = stoi(temp);
+            }
+
+            cout << "Enter new chinese marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].chinese_marks = stoi(temp);
+            }
+
+            cout << "Enter new english marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].english_marks = stoi(temp);
+            }
+
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "sorry but no user found to update record";
+    }else{
+        cout << "1 record updated";
+    }
+}
+
+
+void functionPrint() {
+    cout << endl;
+    cout
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    cout << "" << setw(50) << setfill('-') << "\n";
+    cout << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        cout
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    cout << "\n";
+}
+
+
+void functionImport(){
+    ifstream inFile;
+    ofstream outFile;
+    string student_name, maths_mark, chinese_mark, english_mark, grade;
+    int record_added;
+    record_added = 0;
+
+    string filename;
+
+    cout << "Please enter a file with list of student: ";
+    cin >> filename;
+
+    inFile.open(filename);
+    if (!inFile) {
+        cout << "Cannot open the input file." << endl;
+        // << "The program terminates." << endl;
+        // return 1;
+    }else{
+        while (true){
+            inFile >> student_name;
+
+            if (student_name == "END") {
+                break;
+            }else{
+                inFile >> maths_mark >> chinese_mark >> english_mark;
+                MarksRecord record;
+                record.name = student_name;
+                record.maths_marks = stoi(maths_mark);
+                record.chinese_marks = stoi(chinese_mark);
+                record.english_marks = stoi(english_mark);
+
+                records.push_back(record);
+
+                record_added = record_added + 1;
+            }
+
+        }
+
+        cout << "record imported : " << record_added << "\n";
+        cout << "\n";
+
+
+        inFile.close();
+    }
+
+}
+
+void functionExport(){
+    ofstream outFile;
+    string filename;
+
+    cout << "Please enter a file to export: ";
+    cin >> filename;
+
+    outFile.open(filename);
+
+    outFile << setw(10) << setfill(' ') << ""
+        << "~ STUDENT RECORDS ~";
+    outFile << "\n";
+    outFile << "\n";
+
+    outFile
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    outFile << "" << setw(50) << setfill('-') << "\n";
+    outFile << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        outFile
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    outFile << "\n";
+    cout << "export done !" << "\n";
+}
+
+int main() {
+    char choice;
+    while (true) {
+        print_menu();
+        cin >> choice;
+
+        switch (choice) {
+            case '1': functionAdd(); break;
+            case '2': functionDelete(); break;
+            case '3': functionEdit(); break;
+            case '4': functionPrint(); break;
+            case '5': functionImport(); break;
+            case '6': functionExport(); break;
+
+            // exit handler
+            case 'E':
+            case 'e':
+                return 0;
+
+            // exception handler
+            default:
+                cout << "Invalid choice. Please try again.\n";
+        }
+    }
+
+    return 0;
+}
+

task1/src - Copy/main.cpp

@@ -0,0 +1,299 @@
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+struct MarksRecord {
+    string name;
+    int maths_marks, chinese_marks, english_marks;
+    string grade;
+};
+
+vector<MarksRecord> records;
+
+string functionGetGrade(int maths_marks, int chinese_marks, int english_marks){
+    string grade;
+    int marks_sum;
+    float marks_avg;
+
+    marks_sum = 1;
+    marks_sum = (maths_marks + chinese_marks + english_marks);
+    marks_avg = marks_sum / 3;
+
+    if (marks_avg > 90)  return "A";
+    if (marks_avg > 80)  return "B";
+    if (marks_avg > 70)  return "C";
+    return "D";
+}
+
+void print_menu() {
+    cout << "\n";
+    cout << "Mark Record System\n";
+    cout << "\n";
+    cout << "------------------------------------------\n";
+    cout << "1. Add marks record                       \n";
+    cout << "2. Delete marks record                    \n";
+    cout << "3. Edit marks record                      \n";
+    cout << "4. Print current marks record in system   \n";
+    cout << "5. import records from file               \n";
+    cout << "6. export records to file                 \n";
+    cout << "------------------------------------------\n";
+    cout << "E. Exit\n";
+    cout << "Enter your choice: ";
+}
+
+void functionAdd() {
+    string temp;
+    bool name_pass;
+    name_pass = false;
+
+    MarksRecord record;
+
+    while (!name_pass){
+        bool error;
+        error = false;
+
+        cout << "Enter name: ";
+        cin >> temp;
+
+        for (size_t i = 0; i < records.size(); i++) {
+            if (records[i].name == temp) {
+                error = true;
+                cout << "ERROR: duplicated student name found"<<"\n";
+            }
+        }
+
+        // check if name entered is empty
+        if (temp == string()){
+            error = true;
+        }
+
+        if (!error) {
+            record.name = temp;
+            name_pass = true;
+        }
+    }
+
+    cout << "Enter maths marks: ";
+    cin >> record.maths_marks;
+    cout << "Enter chinese marks: ";
+    cin >> record.chinese_marks;
+    cout << "Enter english marks: ";
+    cin >> record.english_marks;
+
+    records.push_back(record);
+    cout << "1 record added.";
+}
+
+void functionDelete() {
+    string name;
+    bool user_found;
+    user_found = false;
+
+    cout << "Enter name to delete: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            records.erase(records.begin() + i);
+            user_found = true;
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "ERROR: student record not found";
+    }else{
+        cout << "1 record deleted.";
+    }
+}
+
+void functionEdit() {
+    string name;
+    string temp;
+    bool user_found;
+
+    cout << "Enter name to edit: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            user_found = true;
+            cout << "Enter new maths marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].maths_marks = stoi(temp);
+            }
+
+            cout << "Enter new chinese marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].chinese_marks = stoi(temp);
+            }
+
+            cout << "Enter new english marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].english_marks = stoi(temp);
+            }
+
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "sorry but no user found to update record";
+    }else{
+        cout << "1 record updated.";
+    }
+}
+
+
+void functionPrint() {
+    cout << endl;
+    cout
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    cout << "" << setw(50) << setfill('-') << "\n";
+    cout << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        cout
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    cout << "\n";
+}
+
+
+void functionImport(){
+    ifstream inFile;
+    ofstream outFile;
+    string student_name, maths_mark, chinese_mark, english_mark, grade;
+    int record_added;
+    record_added = 0;
+
+    string filename;
+
+    cout << "Please enter a file with list of student: ";
+    cin >> filename;
+
+    inFile.open(filename);
+    if (!inFile) {
+        cout << "Cannot open the input file." << endl;
+        // << "The program terminates." << endl;
+        // return 1;
+    }else{
+        while (true){
+            inFile >> student_name;
+
+            if (student_name == "END") {
+                break;
+            }else{
+                inFile >> maths_mark >> chinese_mark >> english_mark;
+                MarksRecord record;
+                record.name = student_name;
+                record.maths_marks = stoi(maths_mark);
+                record.chinese_marks = stoi(chinese_mark);
+                record.english_marks = stoi(english_mark);
+
+                records.push_back(record);
+
+                record_added = record_added + 1;
+            }
+
+        }
+
+        cout << "record imported : " << record_added << "\n";
+        cout << "\n";
+
+
+        inFile.close();
+    }
+
+}
+
+void functionExport(){
+    ofstream outFile;
+    string filename;
+
+    cout << "Please enter a file to export: ";
+    cin >> filename;
+
+    outFile.open(filename);
+
+    outFile << setw(10) << setfill(' ') << ""
+        << "~ STUDENT RECORDS ~";
+    outFile << "\n";
+    outFile << "\n";
+
+    outFile
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    outFile << "" << setw(50) << setfill('-') << "\n";
+    outFile << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        outFile
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    outFile << "\n";
+    cout << "export done !" << "\n";
+}
+
+int main() {
+    char choice;
+    while (true) {
+        print_menu();
+        cin >> choice;
+
+        switch (choice) {
+            case '1': functionAdd(); break;
+            case '2': functionDelete(); break;
+            case '3': functionEdit(); break;
+            case '4': functionPrint(); break;
+            case '5': functionImport(); break;
+            case '6': functionExport(); break;
+
+            // exit handler
+            case 'E':
+            case 'e':
+                return 0;
+
+            // exception handler
+            default:
+                cout << "Invalid choice. Please try again.\n";
+        }
+    }
+
+    return 0;
+}
+

task1/src - Copy/mark_list.txt

@@ -0,0 +1,5 @@
+Ivy 86 96 83
+Anson 55 70 67
+Mark 56 89 74
+Candy 78 63 97
+END

task1/src-with-comment/bread_example.cpp

@@ -0,0 +1,69 @@
+/**
+ * @file main.cpp
+ * @author Your Name
+ * @brief A brief description of the program.
+ *
+ * A more detailed description of the program.
+ *
+ * @version 0.1
+ * @date 2022-02-28
+ *
+ * @copyright Copyright (c) 2022 Your Name
+ *
+ */
+
+#include <iostream>
+#include <fstream>
+#include <iomanip>
+#include <string>
+
+using namespace std;
+
+/**
+ * @brief A brief description of the main function.
+ *
+ * A more detailed description of the main function.
+ *
+ * @param argc command line argument count
+ * @param argv command line arguments
+ * @return int exit status
+ */
+int main(int argc, char** argv) {
+    // Declare variables
+    ifstream inFile;
+    ofstream outFile;
+    string burger_name, fries_name, icecream_name;
+    int burger_price, fries_price, icecream_price;
+
+    // Open the input file and output file
+    inFile.open("price.txt");
+
+    if (!inFile) {
+        cout << "Cannot open the input file."
+        << "The program terminates." << endl;
+        return 1;
+    }
+
+    outFile.open("price_output.out");
+    cout << "Processing data" << endl;
+
+    // Read file word by word
+    inFile >> burger_name >> burger_price;
+    inFile >> fries_name >> fries_price;
+    inFile >> icecream_name >> icecream_price;
+
+    // Output file
+    outFile << "The price of " << burger_name
+        << " is $" << burger_price <<"." << endl;
+
+    outFile << "The price of " << fries_name
+        << " is $" << fries_price << "." << endl;
+
+    outFile << "The price of " << icecream_name
+        << " is $" << icecream_price << "." << endl;
+    inFile.close(); //.close(): close a file
+    outFile.close();
+    cout << "Processing completed" << endl;
+
+    return 0;
+}

task1/src-with-comment/main.cpp

@@ -0,0 +1,403 @@
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+/**
+ * Represents a structure for storing marks records.
+ *
+ * Attributes:
+ * - name         : a string representing the name of the student
+ * - maths_marks  : an integer representing the marks obtained in maths
+ * - chinese_marks: an integer representing the marks obtained in chinese
+ * - english_marks: an integer representing the marks obtained in english
+ * - grade        : a string representing the grade obtained based on the marks
+ */
+struct MarksRecord {
+    string name;
+    int maths_marks, chinese_marks, english_marks;
+    string grade;
+};
+
+vector<MarksRecord> records;
+
+/**
+ * Calculates the grade based on the average marks obtained in three subjects.
+ *
+ * @param maths_marks The marks obtained in Maths.
+ * @param chinese_marks The marks obtained in Chinese.
+ * @param english_marks The marks obtained in English.
+ * @return The grade based on the average marks.
+ *         - "A" if the average marks are greater than 90.
+ *         - "B" if the average marks are greater than 80.
+ *         - "C" if the average marks are greater than 70.
+ *         - "D" otherwise.
+ */
+string functionGetGrade(int maths_marks, int chinese_marks, int english_marks){
+    string grade;
+    int marks_sum;
+    float marks_avg;
+
+    marks_sum = 1;
+    marks_sum = (maths_marks + chinese_marks + english_marks);
+    marks_avg = marks_sum / 3;
+
+    if (marks_avg > 90)  return "A";
+    if (marks_avg > 80)  return "B";
+    if (marks_avg > 70)  return "C";
+    return "D";
+}
+
+/**
+ * Displays the menu options for the Mark Record System.
+ *
+ * The menu options include:
+ * 1. Add marks record
+ * 2. Delete marks record
+ * 3. Edit marks record
+ * 4. Print current marks record in system
+ * 5. Import records from file
+ * 6. Export records to file
+ * E. Exit
+ *
+ * The user is prompted to enter their choice after the menu is displayed.
+ */
+void print_menu() {
+    cout << "\n";
+    cout << "Mark Record System\n";
+    cout << "\n";
+    cout << "------------------------------------------\n";
+    cout << "1. Add marks record                       \n";
+    cout << "2. Delete marks record                    \n";
+    cout << "3. Edit marks record                      \n";
+    cout << "4. Print current marks record in system   \n";
+    cout << "5. import records from file               \n";
+    cout << "6. export records to file                 \n";
+    cout << "------------------------------------------\n";
+    cout << "E. Exit\n";
+    cout << "Enter your choice: ";
+}
+
+/**
+ * Adds a new marks record to the system.
+ *
+ * Prompts the user to enter the name, maths marks, chinese marks, and english marks for the new record.
+ * Checks if the entered name is already present in the records. If so, displays an error message.
+ * Checks if the entered name is empty. If so, displays an error message.
+ * If all checks pass, creates a new MarksRecord object with the entered details and adds it to the records vector.
+ *
+ */
+void functionAdd() {
+    string temp;
+    bool name_pass;
+    name_pass = false;
+
+    MarksRecord record;
+
+    while (!name_pass){
+        bool error;
+        error = false;
+
+        cout << "Enter name: ";
+        cin >> temp;
+        cin.clear();
+
+        // check if name entered is empty
+        if (temp == string()){
+            error = true;
+        }else if (temp.find(' ') != string::npos){ // check if name contain space
+            cout << "ERROR: name cannot contain space" << endl;
+            error = true;
+        }
+
+        if (!error) {
+            record.name = temp;
+            name_pass = true;
+        }
+    }
+
+    cout << "Enter maths marks: ";
+    cin >> record.maths_marks;
+    cout << "Enter chinese marks: ";
+    cin >> record.chinese_marks;
+    cout << "Enter english marks: ";
+    cin >> record.english_marks;
+
+    records.push_back(record);
+    cout << "1 record added.";
+}
+
+
+/**
+ * Deletes a marks record from the system.
+ *
+ * This function prompts the user to enter the name of the record to be deleted.
+ * It then searches for the record in the 'records' vector and removes it if found.
+ * If the record is not found, an error message is displayed.
+ *
+ */
+void functionDelete() {
+    string name;
+    bool user_found;
+    user_found = false;
+
+    cout << "Enter name to delete: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            records.erase(records.begin() + i);
+            user_found = true;
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "ERROR: student record not found";
+    }else{
+        cout << "1 record deleted.";
+    }
+}
+
+/**
+ * Edit the marks record for a student.
+ *
+ * This function allows the user to edit the marks record for a student by entering the student's name and the new marks for each subject.
+ * The function searches for the student's name in the records vector and updates the marks accordingly.
+ * If the user enters "-" for a subject, the marks for that subject will be skipped and not updated.
+ *
+ */
+void functionEdit() {
+    string name;
+    string temp;
+    bool user_found;
+    user_found = false;
+
+    cout << "Enter name to edit: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            user_found = true;
+            cout << "Enter new maths marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].maths_marks = stoi(temp);
+            }
+
+            cout << "Enter new chinese marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].chinese_marks = stoi(temp);
+            }
+
+            cout << "Enter new english marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].english_marks = stoi(temp);
+            }
+
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "sorry but no user found to update record";
+    }else{
+        cout << "1 record updated.";
+    }
+}
+
+/**
+ * Prints the current marks record in the system.
+ *
+ * This function displays the student records stored in the 'records' vector.
+ * It prints the student name, maths marks, chinese marks, english marks, and grade for each record.
+ * The grade is calculated using the 'functionGetGrade' function.
+ *
+ * Note:
+ * - The records are printed in a tabular format with appropriate spacing.
+ * - The grade is calculated based on the maths marks, chinese marks, and english marks using the 'functionGetGrade' function.
+ */
+void functionPrint() {
+    cout << endl;
+    cout
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    cout << "" << setw(50) << setfill('-') << "\n";
+    cout << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        cout
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    cout << "\n";
+}
+
+/**
+ * Imports records from a file and adds them to the current marks record system.
+ *
+ * This function prompts the user to enter the name of a file containing a list of student records.
+ * It then opens the file and reads each line, extracting the student name, maths marks, chinese marks, and english marks.
+ * A new MarksRecord object is created for each line and added to the records vector.
+ * The function keeps track of the number of records added and displays the total at the end.
+ *
+ * Note:
+ * - The file should be formatted with each line containing the student name, maths marks, chinese marks, and english marks separated by spaces.
+ * - The last line of the file should contain the word "END" to indicate the end of the records.
+ */
+void functionImport(){
+    ifstream inFile;
+    ofstream outFile;
+    string student_name, maths_mark, chinese_mark, english_mark, grade;
+    int record_added;
+    record_added = 0;
+
+    string filename;
+
+    cout << "Please enter a file with list of student: ";
+    cin >> filename;
+
+    inFile.open(filename);
+    if (!inFile) {
+        cout << "Cannot open the input file." << endl;
+        // << "The program terminates." << endl;
+        // return 1;
+    }else{
+        while (true){
+            inFile >> student_name;
+
+            if (student_name == "END") {
+                break;
+            }else{
+                inFile >> maths_mark >> chinese_mark >> english_mark;
+                MarksRecord record;
+                record.name = student_name;
+                record.maths_marks = stoi(maths_mark);
+                record.chinese_marks = stoi(chinese_mark);
+                record.english_marks = stoi(english_mark);
+
+                records.push_back(record);
+
+                record_added = record_added + 1;
+            }
+
+        }
+
+        cout << "record imported : " << record_added << "\n";
+        cout << "\n";
+
+
+        inFile.close();
+    }
+
+}
+
+/**
+ * Exports the student records to a file.
+ *
+ * This function prompts the user to enter the name of the file to export the records to.
+ * It then opens the file and writes the student records in a formatted manner.
+ * The file will contain the student name, maths marks, chinese marks, english marks, and grade for each record.
+ * The function uses the functionGetGrade() function to calculate the grade based on the marks.
+ *
+ * Note:
+ * - The file will be formatted with each record on a separate line.
+ * - The fields will be separated by spaces.
+ * - The file will start with a header line indicating the fields.
+ * - The file will end with an empty line.
+ */
+void functionExport(){
+    ofstream outFile;
+    string filename;
+
+    cout << "Please enter a file to export: ";
+    cin >> filename;
+
+    outFile.open(filename);
+
+    outFile << setw(10) << setfill(' ') << ""
+        << "~ STUDENT RECORDS ~";
+    outFile << "\n";
+    outFile << "\n";
+
+    outFile
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    outFile << "" << setw(50) << setfill('-') << "\n";
+    outFile << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        outFile
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    outFile << "\n";
+    cout << "export done !" << "\n";
+}
+
+/**
+ * Main function of the program.
+ *
+ * This function runs a menu-driven program for managing marks records.
+ * It continuously displays a menu and prompts the user for their choice.
+ * Based on the user's choice, it calls the corresponding functions to perform the desired operation.
+ * The program keeps running until the user chooses to exit (e/E).
+ *
+ */
+int main() {
+    char choice;
+    while (true) {
+        print_menu();
+        cin >> choice;
+
+        switch (choice) {
+            case '1': functionAdd(); break;
+            case '2': functionDelete(); break;
+            case '3': functionEdit(); break;
+            case '4': functionPrint(); break;
+            case '5': functionImport(); break;
+            case '6': functionExport(); break;
+
+            // exit handler
+            case 'E':
+            case 'e':
+                return 0;
+
+            // exception handler
+            default:
+                cout << "Invalid choice. Please try again.\n";
+        }
+    }
+
+    return 0;
+}
+

task1/src-with-comment/mark_list.txt

@@ -0,0 +1,5 @@
+Ivy 86 96 83
+Anson 55 70 67
+Mark 56 89 74
+Candy 78 63 97
+END

task1/src/.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "CodeGPT.apiKey": "CodeGPT Plus Beta"
+}

task1/src/main copy.cpp

@@ -0,0 +1,297 @@
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+struct MarksRecord {
+    string name;
+    int maths_marks, chinese_marks, english_marks;
+    string grade;
+};
+
+vector<MarksRecord> records;
+
+string functionGetGrade(int maths_marks, int chinese_marks, int english_marks){
+    string grade;
+    int marks_sum;
+    float marks_avg;
+
+    marks_sum = 1;
+    marks_sum = (maths_marks + chinese_marks + english_marks);
+    marks_avg = marks_sum / 3;
+
+    if (marks_avg > 90)  return "A";
+    if (marks_avg > 80)  return "B";
+    if (marks_avg > 70)  return "C";
+    return "D";
+}
+
+void print_menu() {
+    cout << "\n";
+    cout << "Mark Record System\n";
+    cout << "\n";
+    cout << "------------------------------------------\n";
+    cout << "1. Add marks record                       \n";
+    cout << "2. Delete marks record                    \n";
+    cout << "3. Edit marks record                      \n";
+    cout << "4. Print current marks record in system   \n";
+    cout << "5. import records from file               \n";
+    cout << "6. export records to file                 \n";
+    cout << "------------------------------------------\n";
+    cout << "E. Exit\n";
+    cout << "Enter your choice: ";
+}
+
+void functionAdd() {
+    string temp;
+    bool name_pass;
+    name_pass = false;
+
+    MarksRecord record;
+
+    while (!name_pass){
+        bool error;
+        error = false;
+
+        cout << "Enter name: ";
+        cin >> temp;
+
+        for (size_t i = 0; i < records.size(); i++) {
+            if (records[i].name == temp) {
+                error = true;
+                cout << "ERROR: duplicated student name found"<<"\n";
+            }
+        }
+
+        // check if name entered is empty
+        if (temp == string()){
+            error = true;
+        }
+
+        if (!error) {
+            record.name = temp;
+            name_pass = true;
+        }
+    }
+
+    cout << "Enter maths marks: ";
+    cin >> record.maths_marks;
+    cout << "Enter chinese marks: ";
+    cin >> record.chinese_marks;
+    cout << "Enter english marks: ";
+    cin >> record.english_marks;
+    records.push_back(record);
+}
+
+void functionDelete() {
+    string name;
+    bool user_found;
+    user_found = false;
+
+    cout << "Enter name to delete: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            records.erase(records.begin() + i);
+            user_found = true;
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "ERROR: student record not found";
+    }else{
+        cout << "1 record deleted.";
+    }
+}
+
+void functionEdit() {
+    string name;
+    string temp;
+    bool user_found;
+
+    cout << "Enter name to edit: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            user_found = true;
+            cout << "Enter new maths marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].maths_marks = stoi(temp);
+            }
+
+            cout << "Enter new chinese marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].chinese_marks = stoi(temp);
+            }
+
+            cout << "Enter new english marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].english_marks = stoi(temp);
+            }
+
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "sorry but no user found to update record";
+    }else{
+        cout << "1 record updated";
+    }
+}
+
+
+void functionPrint() {
+    cout << endl;
+    cout
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    cout << "" << setw(50) << setfill('-') << "\n";
+    cout << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        cout
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    cout << "\n";
+}
+
+
+void functionImport(){
+    ifstream inFile;
+    ofstream outFile;
+    string student_name, maths_mark, chinese_mark, english_mark, grade;
+    int record_added;
+    record_added = 0;
+
+    string filename;
+
+    cout << "Please enter a file with list of student: ";
+    cin >> filename;
+
+    inFile.open(filename);
+    if (!inFile) {
+        cout << "Cannot open the input file." << endl;
+        // << "The program terminates." << endl;
+        // return 1;
+    }else{
+        while (true){
+            inFile >> student_name;
+
+            if (student_name == "END") {
+                break;
+            }else{
+                inFile >> maths_mark >> chinese_mark >> english_mark;
+                MarksRecord record;
+                record.name = student_name;
+                record.maths_marks = stoi(maths_mark);
+                record.chinese_marks = stoi(chinese_mark);
+                record.english_marks = stoi(english_mark);
+
+                records.push_back(record);
+
+                record_added = record_added + 1;
+            }
+
+        }
+
+        cout << "record imported : " << record_added << "\n";
+        cout << "\n";
+
+
+        inFile.close();
+    }
+
+}
+
+void functionExport(){
+    ofstream outFile;
+    string filename;
+
+    cout << "Please enter a file to export: ";
+    cin >> filename;
+
+    outFile.open(filename);
+
+    outFile << setw(10) << setfill(' ') << ""
+        << "~ STUDENT RECORDS ~";
+    outFile << "\n";
+    outFile << "\n";
+
+    outFile
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    outFile << "" << setw(50) << setfill('-') << "\n";
+    outFile << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        outFile
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    outFile << "\n";
+    cout << "export done !" << "\n";
+}
+
+int main() {
+    char choice;
+    while (true) {
+        print_menu();
+        cin >> choice;
+
+        switch (choice) {
+            case '1': functionAdd(); break;
+            case '2': functionDelete(); break;
+            case '3': functionEdit(); break;
+            case '4': functionPrint(); break;
+            case '5': functionImport(); break;
+            case '6': functionExport(); break;
+
+            // exit handler
+            case 'E':
+            case 'e':
+                return 0;
+
+            // exception handler
+            default:
+                cout << "Invalid choice. Please try again.\n";
+        }
+    }
+
+    return 0;
+}
+

task1/src/main.cpp

@@ -0,0 +1,299 @@
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+struct MarksRecord {
+    string name;
+    int maths_marks, chinese_marks, english_marks;
+    string grade;
+};
+
+vector<MarksRecord> records;
+
+string functionGetGrade(int maths_marks, int chinese_marks, int english_marks){
+    string grade;
+    int marks_sum;
+    float marks_avg;
+
+    marks_sum = 1;
+    marks_sum = (maths_marks + chinese_marks + english_marks);
+    marks_avg = marks_sum / 3;
+
+    if (marks_avg > 90)  return "A";
+    if (marks_avg > 80)  return "B";
+    if (marks_avg > 70)  return "C";
+    return "D";
+}
+
+void print_menu() {
+    cout << "\n";
+    cout << "Mark Record System\n";
+    cout << "\n";
+    cout << "------------------------------------------\n";
+    cout << "1. Add marks record                       \n";
+    cout << "2. Delete marks record                    \n";
+    cout << "3. Edit marks record                      \n";
+    cout << "4. Print current marks record in system   \n";
+    cout << "5. import records from file               \n";
+    cout << "6. export records to file                 \n";
+    cout << "------------------------------------------\n";
+    cout << "E. Exit\n";
+    cout << "Enter your choice: ";
+}
+
+void functionAdd() {
+    string temp;
+    bool name_pass;
+    name_pass = false;
+
+    MarksRecord record;
+
+    while (!name_pass){
+        bool error;
+        error = false;
+
+        cout << "Enter name: ";
+        cin >> temp;
+
+        for (size_t i = 0; i < records.size(); i++) {
+            if (records[i].name == temp) {
+                error = true;
+                cout << "ERROR: duplicated student name found"<<"\n";
+            }
+        }
+
+        // check if name entered is empty
+        if (temp == string()){
+            error = true;
+        }
+
+        if (!error) {
+            record.name = temp;
+            name_pass = true;
+        }
+    }
+
+    cout << "Enter maths marks: ";
+    cin >> record.maths_marks;
+    cout << "Enter chinese marks: ";
+    cin >> record.chinese_marks;
+    cout << "Enter english marks: ";
+    cin >> record.english_marks;
+
+    records.push_back(record);
+    cout << "1 record added.";
+}
+
+void functionDelete() {
+    string name;
+    bool user_found;
+    user_found = false;
+
+    cout << "Enter name to delete: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            records.erase(records.begin() + i);
+            user_found = true;
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "ERROR: student record not found";
+    }else{
+        cout << "1 record deleted.";
+    }
+}
+
+void functionEdit() {
+    string name;
+    string temp;
+    bool user_found;
+
+    cout << "Enter name to edit: ";
+    cin >> name;
+    for (size_t i = 0; i < records.size(); i++) {
+        if (records[i].name == name) {
+            user_found = true;
+            cout << "Enter new maths marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].maths_marks = stoi(temp);
+            }
+
+            cout << "Enter new chinese marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].chinese_marks = stoi(temp);
+            }
+
+            cout << "Enter new english marks [- to skip]: ";
+            cin >> temp;
+            if (temp != "-") {
+                records[i].english_marks = stoi(temp);
+            }
+
+            break;
+        }
+    }
+
+    if (!user_found){
+        cout << "sorry but no user found to update record";
+    }else{
+        cout << "1 record updated.";
+    }
+}
+
+
+void functionPrint() {
+    cout << endl;
+    cout
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    cout << "" << setw(50) << setfill('-') << "\n";
+    cout << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        cout
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    cout << "\n";
+}
+
+
+void functionImport(){
+    ifstream inFile;
+    ofstream outFile;
+    string student_name, maths_mark, chinese_mark, english_mark, grade;
+    int record_added;
+    record_added = 0;
+
+    string filename;
+
+    cout << "Please enter a file with list of student: ";
+    cin >> filename;
+
+    inFile.open(filename);
+    if (!inFile) {
+        cout << "Cannot open the input file." << endl;
+        // << "The program terminates." << endl;
+        // return 1;
+    }else{
+        while (true){
+            inFile >> student_name;
+
+            if (student_name == "END") {
+                break;
+            }else{
+                inFile >> maths_mark >> chinese_mark >> english_mark;
+                MarksRecord record;
+                record.name = student_name;
+                record.maths_marks = stoi(maths_mark);
+                record.chinese_marks = stoi(chinese_mark);
+                record.english_marks = stoi(english_mark);
+
+                records.push_back(record);
+
+                record_added = record_added + 1;
+            }
+
+        }
+
+        cout << "record imported : " << record_added << "\n";
+        cout << "\n";
+
+
+        inFile.close();
+    }
+
+}
+
+void functionExport(){
+    ofstream outFile;
+    string filename;
+
+    cout << "Please enter a file to export: ";
+    cin >> filename;
+
+    outFile.open(filename);
+
+    outFile << setw(10) << setfill(' ') << ""
+        << "~ STUDENT RECORDS ~";
+    outFile << "\n";
+    outFile << "\n";
+
+    outFile
+        << setw(10) << setfill(' ') << left << "Name" << setw(10)
+        << setw(10) << setfill(' ') << left << "Maths" << setw(10)
+        << setw(10) << setfill(' ') << left << "Chinese" << setw(10)
+        << setw(10) << setfill(' ') << left << "English" << setw(10)
+        << setw(10) << setfill(' ') << left << "Grade" << setw(10);
+
+    outFile << "" << setw(50) << setfill('-') << "\n";
+    outFile << "\n";
+
+    for (const auto& record : records) {
+        string calc_grade;
+        calc_grade = functionGetGrade(record.maths_marks, record.chinese_marks, record.english_marks);
+
+        outFile
+            << setw(10) << setfill(' ') << left << record.name
+            << setw(10) << setfill(' ') << left << record.maths_marks
+            << setw(10) << setfill(' ') << left << record.chinese_marks
+            << setw(10) << setfill(' ') << left << record.english_marks
+
+            // append 2 chars on the left
+            << setw(2) << setfill(' ') << left << " "
+            << setw(10) << setfill(' ') << left << calc_grade  << "\n";
+    }
+    outFile << "\n";
+    cout << "export done !" << "\n";
+}
+
+int main() {
+    char choice;
+    while (true) {
+        print_menu();
+        cin >> choice;
+
+        switch (choice) {
+            case '1': functionAdd(); break;
+            case '2': functionDelete(); break;
+            case '3': functionEdit(); break;
+            case '4': functionPrint(); break;
+            case '5': functionImport(); break;
+            case '6': functionExport(); break;
+
+            // exit handler
+            case 'E':
+            case 'e':
+                return 0;
+
+            // exception handler
+            default:
+                cout << "Invalid choice. Please try again.\n";
+        }
+    }
+
+    return 0;
+}
+

task1/src/mark_list.txt

@@ -0,0 +1,5 @@
+Ivy 86 96 83
+Anson 55 70 67
+Mark 56 89 74
+Candy 78 63 97
+END

task2/build.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+set -ex
+
+# g++ -o output helloworld.cpp
+g++ -o output main.cpp
+
+echo "build done"
+
+./output

task2/deliver/main.cpp

@@ -0,0 +1,185 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+
+// 2. pseudo code of the algorithm
+// convert to postfix expression use stack,
+// 1. if it is an operand, add to postfix,
+// 2. if it is an operator,
+//      2.1 if it is the first operator, push into `s` stack
+//      2.2 if `s` stack already got element, compare the weight of opreators
+//      2.3 pop `s` stack until the top most one got smaller precedence
+// 3. if it is a bracket, push into stack `s`,
+// 3. if it is a closing bracket, pop all element from `s` stack back to postfix,
+// else return the result
+
+// Function to convert infix expression to postfix expression
+std::string infixToPostfix(const std::string &infix)
+{
+    std::stack<char> s;
+    std::string postfix;
+    std::map<char, int> precedence = {{'+', 1}, {'-', 1}, {'*', 2}, {'/', 2}, {'(', 0}};
+
+    for (char c : infix)
+    {
+        if (std::isalnum(c))
+        { // 1. if operand, add to postfix
+            postfix += c;
+        }
+
+        // 其實括號入面同括號出面嘅數你當佢兩條式計就得
+        else if (c == '(')
+        { // 2. if '(', push to stack
+            s.push(c);
+        }
+
+        // 咁佢呢度關括號呀嘛,
+        // 咁佢咪會由個 stack 嗰度 port 返曬啲operator出嚟囉, 變咗可以 14+5*
+        else if (c == ')')
+        { // 3. if ')', pop until '('
+            while (!s.empty() && s.top() != '(')
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            if (!s.empty())
+                s.pop(); // pop '('
+        }
+        else
+        { // 4. if operator, pop operators with greater or equal precedence
+            while (!s.empty() && precedence[c] <= precedence[s.top()])
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            s.push(c); // push current operator
+        }
+    }
+
+    // 5. pop remaining operators, LIFO
+    while (!s.empty())
+    {
+        postfix += s.top();
+        s.pop();
+    }
+
+    return postfix;
+}
+
+// Function to evaluate postfix expression
+
+// 2. pseudo code of the algorithm
+// evaluate a postfix expression use stack,
+// if it is an operand, push it into stack,
+// if it is an operator, pop the top two elements, apply the operator, and push the result,
+// if it is a bracket, pop until the matched bracket, then push it into stack,
+// if the input is end, return the last element in stack,
+// else error
+
+int evaluatePostfix(const std::string &postfix)
+{
+    std::stack<int> s;
+
+    for (char c : postfix)
+    {
+        if (std::isdigit(c))
+        { // 1. if operand, push to stack
+            s.push(c - '0');
+        }
+        else
+        { // 2. if operator, pop two operands, evaluate and push result
+            int op2 = s.top();
+            s.pop();
+            int op1 = s.top();
+            s.pop();
+            switch (c)
+            {
+            case '+':
+                s.push(op1 + op2);
+                break;
+            case '-':
+                s.push(op1 - op2);
+                break;
+            case '*':
+                s.push(op1 * op2);
+                break;
+            case '/':
+                s.push(op1 / op2);
+                break;
+            }
+        }
+    }
+    return s.top(); // 3. result is the only element in stack
+}
+
+int main()
+{
+    std::string infix;
+    // std::cout << "Enter an arithmetic expression: ";
+    // std::getline(std::cin, infix);
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+
+    // 1,20,+
+    // 21
+    std::cout << "e.g. 1 1+4*5" << std::endl;
+    infix = "1+4*5";
+    std::string postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    int result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,+,5,*
+    // 5,5,*
+    // 25
+    std::cout << "e.g. 2 (1+4)*5" << std::endl;
+    infix = "(1+4)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,+,5,-
+    // 5,5,-
+    // 0
+    std::cout << "e.g. 3 1+4-5" << std::endl;
+    infix = "1+4-5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+,5,*
+    // 1,20,+,5,*
+    // 21,5,*
+    // 105
+    std::cout << "e.g. 4 (1+4*5)*5" << std::endl;
+    infix = "(1+4*5)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+,2,5,*,-
+    // =>1,20,+,2,5,*,-
+    // =>21,2,5,*,-
+    // =>21,10,-
+    // =>11
+    std::cout << "e.g. 5 (1+4*5)-2*5" << std::endl;
+    infix = "(1+4*5)-2*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    return 0;
+}

task2/deliver_1/main.cpp

@@ -0,0 +1,363 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+#include <string.h>
+#include <stdio.h>
+#include <queue>
+#include <algorithm>
+#include <cassert>
+
+// 1. Part 1 can create correct post-fix expression from the input
+// (The operators are addition and multiplication.
+// All the operands are positive integers between 1 and 9)                                           (10%)
+
+// 2. Part 2 can evaluate the simple post-fix expression correctly
+// (The operators are addition and multiplication,
+// all the operands are positive integers between 1 and 9.
+// In the post-fix expression, all the operands and operators are separated by a “ ”.) (10%)
+
+// 3. The operands can be any positive integers.           (5%)
+// 4. The operands can be negative integers.               (5%)
+// 5. The operands can be float numbers.                   (5%)
+// 6. The operators can be “-, /, ^, (, )”.                (5%)
+
+// 2. pseudo code of the algorithm
+// convert to postfix expression use stack,
+// 1. if it is an operand, add to postfix,
+// 2. if it is an operator,
+//      2.1 if it is the first operator, push into `s` stack
+//      2.2 if `s` stack already got element, compare the weight of opreators
+//      2.3 pop `s` stack until the top most one got smaller precedence
+// 3. if it is a bracket, push into stack `s`,
+// 3. if it is a closing bracket, pop all element from `s` stack back to postfix,
+// else return the result
+
+/**
+ * check if a string is a number
+ * @param str_test the string to check
+ * @return true if the string is a number, false otherwise
+ */
+bool checkIsNumber(std::string &str_test)
+{
+  bool output = true;
+
+  // check if the string is longer than 1 character
+  if (str_test.length() > 1)
+  {
+    // check each character in the string
+    for (auto &c : str_test)
+    {
+      // if the character is not a digit, a dot or a minus sign
+      if (!(('1' <= c && c <= '9') || c == '.' || c == '-'))
+      {
+        // set the output to false
+        output = false;
+        // break the loop
+        break;
+      }
+    }
+  }
+  else
+  {
+    // if the string is only one character long
+    char c = str_test[0];
+    // if the character is not a digit
+    if (!(('1' <= c && c <= '9')))
+    {
+      // set the output to false
+      output = false;
+    }
+  }
+
+  return output;
+}
+
+// 1. Part 1 can create correct post-fix expression from the input
+std::queue<std::string> infixToPostfix(const std::string &infix)
+{
+  std::queue<std::string> output;
+  std::stack<std::string> ss;
+  std::queue<std::string> q_postfix;
+  std::string postfix_temp;
+  std::map<std::string, int> q_precedence = {{"+", 1}, {"-", 1}, {"*", 2}, {"/", 2}, {"(", 0}, {"^", 3}};
+  std::stack<char *> sc;
+  std::queue<std::string> q;
+
+  const char s_delimit[2] = " ";
+  char *token;
+  // seperated by delimiter space
+  token = strtok(const_cast<char *>(infix.c_str()), s_delimit);
+  while (token != NULL)
+  {
+    q.push(token);
+    token = strtok(NULL, s_delimit);
+  }
+
+  while (!q.empty())
+  {
+    std::string temp = q.front();
+    q.pop();
+
+    if (checkIsNumber(temp))
+    {
+      q_postfix.push(temp);
+    }
+
+    // 其實括號入面同括號出面嘅數你當佢兩條式計就得
+    else if (temp.compare("(") == 0)
+    {
+      // 2. if '(', push to stack
+      ss.push(temp);
+    }
+
+    // 咁佢呢度關括號呀嘛,
+    // 咁佢咪會由個 stack 嗰度 port 返曬啲operator出嚟囉, 1+4*5 變咗 145*+
+    // 永遠解開 operator都係會向由左向右
+    else if (temp.compare(")") == 0)
+    {
+      while (!ss.empty() && ss.top() != "(")
+      {
+        q_postfix.push(ss.top());
+        ss.pop();
+      }
+
+      if (!ss.empty())
+        ss.pop(); // pop '('
+    }
+    else
+    {
+      // 4. if operator, pop operators with greater or equal precedence
+      // 比較兩個 operand 之間個先後次序, 數字大嘅計先
+      while (!ss.empty() && q_precedence[temp] <= q_precedence[ss.top()])
+      {
+        q_postfix.push(ss.top());
+        ss.pop();
+      }
+      ss.push(temp); // push current operator
+    }
+  }
+
+  // 5. pop last operator
+  while (!ss.empty())
+  {
+    q_postfix.push(ss.top());
+    ss.pop();
+  }
+
+  return q_postfix;
+}
+
+float evaluatePostfix(std::queue<std::string> &postfix)
+{
+  std::stack<float> s;
+  std::string element = postfix.front();
+
+  std::cout << "Corresponding postfix expression: ";
+
+  while (!postfix.empty())
+  {
+    // 獨立 pop 番佢出嚟
+    std::string element = postfix.front();
+    postfix.pop();
+    std::cout << element << ' ';
+
+    if (checkIsNumber(element))
+    { // 1. if operand, push to stack
+      s.push(std::stof(element));
+    }
+    else
+    {
+      // 如果見到係operator, 攞返嗰兩粒數字出嚟計計佢
+      float op2 = s.top();
+      s.pop();
+      float op1 = s.top();
+      s.pop();
+
+      switch (element[0])
+      {
+      case '+':
+        s.push(op1 + op2);
+        break;
+      case '-':
+        s.push(op1 - op2);
+        break;
+      case '*':
+        s.push(op1 * op2);
+        break;
+      case '/':
+        s.push(op1 / op2);
+        break;
+      case '^':
+        float temp = op1;
+        for (float i = 0; i < op2 - 1; i++)
+        {
+          op1 = op1 * temp;
+        }
+        s.push(op1);
+        break;
+      }
+    }
+  }
+
+  std::cout << std::endl;
+
+  return s.top();
+}
+
+int main()
+{
+  std::queue<std::string> q_temp;
+  std::string infix;
+  float result = 0;
+
+  infix = "1 + 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == 3);
+
+  // 3. The operands can be any positive integers.           (5%)
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "1 + 2 - 3 + 4 - 5 + 6 - 7 + 8 - 9";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == -3);
+
+  // 3. The operands can be any positive integers.           (5%)
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "1 + 2 - 3 * 4 / 5 + 6 - 7 * 8 + 9";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - -40.4) < 0.0001);
+
+  // 4. The operands can be negative integers.               (5%)
+  infix = "-1 + 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == 1);
+
+  // 4. The operands can be negative integers.               (5%)
+  infix = "1 + -2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == -1);
+
+  // 4. The operands can be negative integers.               (5%)
+  infix = "-1 + -2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == -3);
+
+  // 5. The operands can be float numbers.                   (5%)
+  infix = "1.1 + 2.1";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 3.2) < 0.001);
+
+  // 5. The operands can be float numbers.                   (5%)
+  // 4. The operands can be negative integers.               (5%)
+  infix = "-1.1 + 2.3";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 1.2) < 0.001);
+
+  // 5. The operands can be float numbers.                   (5%)
+  infix = "1.1 * 6";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 6.6) < 0.001);
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "1 + 2 ^ 3";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == 9);
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 1 + 4 ) * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 25);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 1 + 4 * 5 ) * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 105);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 1 + 4 * 5 ) - 2 * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 11);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 11 + 4 * 5 ) - 6 * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 1);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 5. The operands can be float numbers.                   (5%)
+  // 6. The operators can be “-, /, ^, (, )”.
+  infix = "( 1.1 + 4 ) * 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(std::abs(result - 10.2) < 0.001);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 5. The operands can be float numbers.                   (5%)
+  // 6. The operators can be “-, /, ^, (, )”.
+  infix = "( 1 + 2 * 3 ) * 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(std::abs(result - 10.2) < 0.001);
+  std::cout << "result: " << result << std::endl;
+
+  std::cout << "Enter an arithmetic expression: ";
+  std::getline(std::cin, infix);
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+
+  std::cout << "done" << std::endl;
+
+  return 0;
+}

task2/gitUpdate.bat

@@ -0,0 +1,7 @@
+git status .
+
+@pause
+
+git add .
+git commit -m"update marissa.sam task2,"
+start git push

task2/helloworld.cpp

@@ -0,0 +1,8 @@
+#include <iostream>
+
+int main()
+{
+    std::cout<<"Hello World";
+
+    return 0;
+}

task2/main.cpp

@@ -0,0 +1,363 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+#include <string.h>
+#include <stdio.h>
+#include <queue>
+#include <algorithm>
+#include <cassert>
+
+// 1. Part 1 can create correct post-fix expression from the input
+// (The operators are addition and multiplication.
+// All the operands are positive integers between 1 and 9)                                           (10%)
+
+// 2. Part 2 can evaluate the simple post-fix expression correctly
+// (The operators are addition and multiplication,
+// all the operands are positive integers between 1 and 9.
+// In the post-fix expression, all the operands and operators are separated by a “ ”.) (10%)
+
+// 3. The operands can be any positive integers.           (5%)
+// 4. The operands can be negative integers.               (5%)
+// 5. The operands can be float numbers.                   (5%)
+// 6. The operators can be “-, /, ^, (, )”.                (5%)
+
+// 2. pseudo code of the algorithm
+// convert to postfix expression use stack,
+// 1. if it is an operand, add to postfix,
+// 2. if it is an operator,
+//      2.1 if it is the first operator, push into `s` stack
+//      2.2 if `s` stack already got element, compare the weight of opreators
+//      2.3 pop `s` stack until the top most one got smaller precedence
+// 3. if it is a bracket, push into stack `s`,
+// 3. if it is a closing bracket, pop all element from `s` stack back to postfix,
+// else return the result
+
+/**
+ * check if a string is a number
+ * @param str_test the string to check
+ * @return true if the string is a number, false otherwise
+ */
+bool checkIsNumber(std::string &str_test)
+{
+  bool output = true;
+
+  // check if the string is longer than 1 character
+  if (str_test.length() > 1)
+  {
+    // check each character in the string
+    for (auto &c : str_test)
+    {
+      // if the character is not a digit, a dot or a minus sign
+      if (!(('1' <= c && c <= '9') || c == '.' || c == '-'))
+      {
+        // set the output to false
+        output = false;
+        // break the loop
+        break;
+      }
+    }
+  }
+  else
+  {
+    // if the string is only one character long
+    char c = str_test[0];
+    // if the character is not a digit
+    if (!(('1' <= c && c <= '9')))
+    {
+      // set the output to false
+      output = false;
+    }
+  }
+
+  return output;
+}
+
+// 1. Part 1 can create correct post-fix expression from the input
+std::queue<std::string> infixToPostfix(const std::string &infix)
+{
+  std::queue<std::string> output;
+  std::stack<std::string> ss;
+  std::queue<std::string> q_postfix;
+  std::string postfix_temp;
+  std::map<std::string, int> q_precedence = {{"+", 1}, {"-", 1}, {"*", 2}, {"/", 2}, {"(", 0}, {"^", 3}};
+  std::stack<char *> sc;
+  std::queue<std::string> q;
+
+  const char s_delimit[2] = " ";
+  char *token;
+  // seperated by delimiter space
+  token = strtok(const_cast<char *>(infix.c_str()), s_delimit);
+  while (token != NULL)
+  {
+    q.push(token);
+    token = strtok(NULL, s_delimit);
+  }
+
+  while (!q.empty())
+  {
+    std::string temp = q.front();
+    q.pop();
+
+    if (checkIsNumber(temp))
+    {
+      q_postfix.push(temp);
+    }
+
+    // 其實括號入面同括號出面嘅數你當佢兩條式計就得
+    else if (temp.compare("(") == 0)
+    {
+      // 2. if '(', push to stack
+      ss.push(temp);
+    }
+
+    // 咁佢呢度關括號呀嘛,
+    // 咁佢咪會由個 stack 嗰度 port 返曬啲operator出嚟囉, 1+4*5 變咗 145*+
+    // 永遠解開 operator都係會向由左向右
+    else if (temp.compare(")") == 0)
+    {
+      while (!ss.empty() && ss.top() != "(")
+      {
+        q_postfix.push(ss.top());
+        ss.pop();
+      }
+
+      if (!ss.empty())
+        ss.pop(); // pop '('
+    }
+    else
+    {
+      // 4. if operator, pop operators with greater or equal precedence
+      // 比較兩個 operand 之間個先後次序, 數字大嘅計先
+      while (!ss.empty() && q_precedence[temp] <= q_precedence[ss.top()])
+      {
+        q_postfix.push(ss.top());
+        ss.pop();
+      }
+      ss.push(temp); // push current operator
+    }
+  }
+
+  // 5. pop last operator
+  while (!ss.empty())
+  {
+    q_postfix.push(ss.top());
+    ss.pop();
+  }
+
+  return q_postfix;
+}
+
+float evaluatePostfix(std::queue<std::string> &postfix)
+{
+  std::stack<float> s;
+  std::string element = postfix.front();
+
+  std::cout << "Corresponding postfix expression: ";
+
+  while (!postfix.empty())
+  {
+    // 獨立 pop 番佢出嚟
+    std::string element = postfix.front();
+    postfix.pop();
+    std::cout << element << ' ';
+
+    if (checkIsNumber(element))
+    { // 1. if operand, push to stack
+      s.push(std::stof(element));
+    }
+    else
+    {
+      // 如果見到係operator, 攞返嗰兩粒數字出嚟計計佢
+      float op2 = s.top();
+      s.pop();
+      float op1 = s.top();
+      s.pop();
+
+      switch (element[0])
+      {
+      case '+':
+        s.push(op1 + op2);
+        break;
+      case '-':
+        s.push(op1 - op2);
+        break;
+      case '*':
+        s.push(op1 * op2);
+        break;
+      case '/':
+        s.push(op1 / op2);
+        break;
+      case '^':
+        float temp = op1;
+        for (float i = 0; i < op2 - 1; i++)
+        {
+          op1 = op1 * temp;
+        }
+        s.push(op1);
+        break;
+      }
+    }
+  }
+
+  std::cout << std::endl;
+
+  return s.top();
+}
+
+int main()
+{
+  std::queue<std::string> q_temp;
+  std::string infix;
+  float result = 0;
+
+  infix = "1 + 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == 3);
+
+  // 3. The operands can be any positive integers.           (5%)
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "1 + 2 - 3 + 4 - 5 + 6 - 7 + 8 - 9";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == -3);
+
+  // 3. The operands can be any positive integers.           (5%)
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "1 + 2 - 3 * 4 / 5 + 6 - 7 * 8 + 9";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - -40.4) < 0.0001);
+
+  // 4. The operands can be negative integers.               (5%)
+  infix = "-1 + 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == 1);
+
+  // 4. The operands can be negative integers.               (5%)
+  infix = "1 + -2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == -1);
+
+  // 4. The operands can be negative integers.               (5%)
+  infix = "-1 + -2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == -3);
+
+  // 5. The operands can be float numbers.                   (5%)
+  infix = "1.1 + 2.1";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 3.2) < 0.001);
+
+  // 5. The operands can be float numbers.                   (5%)
+  // 4. The operands can be negative integers.               (5%)
+  infix = "-1.1 + 2.3";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 1.2) < 0.001);
+
+  // 5. The operands can be float numbers.                   (5%)
+  infix = "1.1 * 6";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 6.6) < 0.001);
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "1 + 2 ^ 3";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(result == 9);
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 1 + 4 ) * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 25);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 1 + 4 * 5 ) * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 105);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 1 + 4 * 5 ) - 2 * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 11);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 6. The operators can be “-, /, ^, (, )”.                (5%)
+  infix = "( 11 + 4 * 5 ) - 6 * 5";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(result == 1);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 5. The operands can be float numbers.                   (5%)
+  // 6. The operators can be “-, /, ^, (, )”.
+  infix = "( 1.1 + 4 ) * 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  assert(std::abs(result - 10.2) < 0.001);
+  std::cout << "result: " << result << std::endl;
+
+  //
+  // 5. The operands can be float numbers.                   (5%)
+  // 6. The operators can be “-, /, ^, (, )”.
+  infix = "1 + ( 1 + ( 1 + 2 ^ 3 ) * 3 ^ 2 ) * 2";
+  std::cout << "e.g. " << infix << std::endl;
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+  assert(std::abs(result - 165) < 0.001);
+
+  std::cout << "Enter an arithmetic expression: ";
+  std::getline(std::cin, infix);
+  q_temp = infixToPostfix(infix);
+  result = evaluatePostfix(q_temp);
+  std::cout << "result: " << result << std::endl;
+
+  std::cout << "done" << std::endl;
+
+  return 0;
+}

task2/notes.md

@@ -0,0 +1,30 @@
+我跟住佢 part1 part2 個方向去做個 source code, 但係 report 嗰部分我就唔需要做, 我諗你係咁嘅意思係咪?
+
+# NOTES
+
+The project requires you to write a simple calculator to evaluate arithmetic expressions. It
+includes two parts:
+
+- In the first part, you need to convert the input to a postfix expression.
+- In the second part, you need to evaluate the postfix expression that you get in the first
+  part.
+- You need to implement your algorithms using c++. Submit your code to Moodle.
+- You also need to write a report explaining the following items.
+
+## Part 1: Convert an expression to postfix expression using stack in STL
+
+1. how to read and store the input?
+2. pseudo code of the algorithm
+3. data structures used in the algorithm
+4. time complexity
+5. space complexity
+6. how to store the postfix expression?
+
+## Part 2: Use stack of STL to evaluate a postfix expression
+
+1. how to read the postfix expression
+2. pseudo code of the algorithm
+3. data structures used in the algorithm
+4. time complexity
+5. space complexity
+6. how to output the final result?

task2/strtok_tryout.cpp

@@ -0,0 +1,22 @@
+#include <string.h>
+#include <stdio.h>
+
+int main()
+{
+  char str[80] = "This is - www.tutorialspoint.com - website";
+  const char s_delimit[2] = "-";
+  char *token;
+
+  /* get the first token */
+  token = strtok(str, s_delimit);
+
+  /* walk through other tokens */
+  while (token != NULL)
+  {
+    printf("%s\n", token);
+
+    token = strtok(NULL, s_delimit);
+  }
+
+  return (0);
+}

task2/temp/.vscode/settings.json

@@ -0,0 +1,91 @@
+{
+    "files.associations": {
+        "*.mjson": "jsonc",
+        "any": "cpp",
+        "array": "cpp",
+        "atomic": "cpp",
+        "barrier": "cpp",
+        "bit": "cpp",
+        "*.tcc": "cpp",
+        "bitset": "cpp",
+        "cctype": "cpp",
+        "cfenv": "cpp",
+        "charconv": "cpp",
+        "chrono": "cpp",
+        "cinttypes": "cpp",
+        "clocale": "cpp",
+        "cmath": "cpp",
+        "codecvt": "cpp",
+        "compare": "cpp",
+        "complex": "cpp",
+        "concepts": "cpp",
+        "condition_variable": "cpp",
+        "coroutine": "cpp",
+        "csetjmp": "cpp",
+        "csignal": "cpp",
+        "cstdarg": "cpp",
+        "cstddef": "cpp",
+        "cstdint": "cpp",
+        "cstdio": "cpp",
+        "cstdlib": "cpp",
+        "cstring": "cpp",
+        "ctime": "cpp",
+        "cuchar": "cpp",
+        "cwchar": "cpp",
+        "cwctype": "cpp",
+        "deque": "cpp",
+        "forward_list": "cpp",
+        "list": "cpp",
+        "map": "cpp",
+        "set": "cpp",
+        "string": "cpp",
+        "unordered_map": "cpp",
+        "unordered_set": "cpp",
+        "vector": "cpp",
+        "exception": "cpp",
+        "algorithm": "cpp",
+        "functional": "cpp",
+        "iterator": "cpp",
+        "memory": "cpp",
+        "memory_resource": "cpp",
+        "numeric": "cpp",
+        "optional": "cpp",
+        "random": "cpp",
+        "ratio": "cpp",
+        "regex": "cpp",
+        "source_location": "cpp",
+        "string_view": "cpp",
+        "system_error": "cpp",
+        "tuple": "cpp",
+        "type_traits": "cpp",
+        "utility": "cpp",
+        "fstream": "cpp",
+        "future": "cpp",
+        "initializer_list": "cpp",
+        "iomanip": "cpp",
+        "iosfwd": "cpp",
+        "iostream": "cpp",
+        "istream": "cpp",
+        "latch": "cpp",
+        "limits": "cpp",
+        "mutex": "cpp",
+        "new": "cpp",
+        "numbers": "cpp",
+        "ostream": "cpp",
+        "ranges": "cpp",
+        "scoped_allocator": "cpp",
+        "semaphore": "cpp",
+        "shared_mutex": "cpp",
+        "span": "cpp",
+        "sstream": "cpp",
+        "stdexcept": "cpp",
+        "stop_token": "cpp",
+        "streambuf": "cpp",
+        "syncstream": "cpp",
+        "thread": "cpp",
+        "typeindex": "cpp",
+        "typeinfo": "cpp",
+        "valarray": "cpp",
+        "variant": "cpp"
+    }
+}

task2/temp/_draft/helloworld copy 2.cpp

@@ -0,0 +1,123 @@
+#include <iostream>
+#include <stack>
+#include <cctype>
+#include <cstring>
+
+// 1. how to read and store the input?
+std::string readInput()
+{
+    std::string input;
+    char c;
+    while (std::cin.get(c)) {
+        if (c == '\n')
+            break;
+        input += c;
+    }
+    return input;
+}
+
+// 2. pseudo code of the algorithm
+// convert to postfix expression use stack, 
+// 1. if it is an operand, push it into stack, 
+// 2. if it is an operator,  pop the top two elements and push the operator result, 
+// 3. if it is a bracket, pop until the matched bracket, then push it into stack, 
+// 4. if the input is end, pop all the remaining elements, 
+// 5. if the last element is a bracket, return error, 
+// else return the result
+std::string infixToPostfix(const std::string& input)
+{
+    std::stack<char> stack;
+    std::string postfix;
+    const char* precedence = "+-*/()";
+    for (const auto& c : input) {
+        if (std::isalpha(c) || std::isdigit(c)) {
+            postfix += c;
+        } else if (c == '(') {
+            stack.push(c);
+        } else if (c == ')') {
+            while (!stack.empty() && stack.top() != '(') {
+                postfix += stack.top();
+                stack.pop();
+            }
+            if (!stack.empty()) {
+                stack.pop();
+            }
+        } else {
+            while (!stack.empty() && precedence[c] <= precedence[stack.top()]) {
+                postfix += stack.top();
+                stack.pop();
+            }
+            stack.push(c);
+        }
+    }
+    while (!stack.empty()) {
+        postfix += stack.top();
+        stack.pop();
+    }
+    return postfix;
+}
+
+// 3. data structures used in the algorithm
+// stack
+// string
+
+// 4. time complexity
+// O(n), where n is the length of input
+
+// 5. space complexity
+// O(n), where n is the length of input
+
+// 6. how to store the postfix expression?
+// using string
+
+int main()
+{
+    std::string input = readInput();
+    std::string postfix = infixToPostfix(input);
+    std::cout << postfix << std::endl;
+
+    // 1. how to read the postfix expression
+    // read postfix expression from standard input stream and store them into string
+
+    // 2. pseudo code of the algorithm
+    // evaluate a postfix expression use stack, 
+    // if it is an operand, push it into stack, 
+    // if it is an operator, pop the top two elements, apply the operator, and push the result, 
+    // if it is a bracket, pop until the matched bracket, then push it into stack, 
+    // if the input is end, return the last element in stack, 
+    // else error
+    std::stack<int> stack;
+    const char* operators = "+-*/";
+    for (const auto& c : postfix) {
+        if (std::isalpha(c) || std::isdigit(c)) {
+            stack.push(c - '0');
+        } else if (std::strchr(operators, c)) {
+            int operand2 = stack.top();
+            stack.pop();
+            int operand1 = stack.top();
+            stack.pop();
+
+            switch (c) {
+            case '+':
+                stack.push(operand1 + operand2);
+                break;
+            case '-':
+                stack.push(operand1 - operand2);
+                break;
+            case '*':
+                stack.push(operand1 * operand2);
+                break;
+            case '/':
+                stack.push(operand1 / operand2);
+                break;
+            default:
+                return -1;
+            }
+        } else {
+            return -1;
+        }
+    }
+    std::cout << stack.top() << std::endl;
+
+    return 0;
+}

task2/temp/_draft/helloworld copy 3.cpp

@@ -0,0 +1,121 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+
+// Function to convert infix expression to postfix expression
+std::string infixToPostfix(const std::string &infix)
+{
+    std::stack<char> s;
+    std::string postfix;
+    std::map<char, int> precedence = {{'+', 1}, {'-', 1}, {'*', 2}, {'/', 2}, {'(', 0}};
+
+    for (char c : infix)
+    {
+        if (std::isalnum(c))
+        { // 1. if operand, add to postfix
+            postfix += c;
+        }
+        else if (c == '(')
+        { // 2. if '(', push to stack
+            s.push(c);
+        }
+        else if (c == ')')
+        { // 3. if ')', pop until '('
+            while (!s.empty() && s.top() != '(')
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            if (!s.empty())
+                s.pop(); // pop '('
+        }
+        else
+        { // 4. if operator, pop operators with greater or equal precedence
+            while (!s.empty() && precedence[c] <= precedence[s.top()])
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            s.push(c); // push current operator
+        }
+    }
+    // 5. pop remaining operators
+    while (!s.empty())
+    {
+        postfix += s.top();
+        s.pop();
+    }
+    return postfix;
+}
+
+// Function to evaluate postfix expression
+int evaluatePostfix(const std::string &postfix)
+{
+    std::stack<int> s;
+
+    for (char c : postfix)
+    {
+        if (std::isdigit(c))
+        { // 1. if operand, push to stack
+            s.push(c - '0');
+        }
+        else
+        { // 2. if operator, pop two operands, evaluate and push result
+            int op2 = s.top();
+            s.pop();
+            int op1 = s.top();
+            s.pop();
+            switch (c)
+            {
+            case '+':
+                s.push(op1 + op2);
+                break;
+            case '-':
+                s.push(op1 - op2);
+                break;
+            case '*':
+                s.push(op1 * op2);
+                break;
+            case '/':
+                s.push(op1 / op2);
+                break;
+            }
+        }
+    }
+    return s.top(); // 3. result is the only element in stack
+}
+
+int main()
+{
+    std::string infix;
+    // std::cout << "Enter an arithmetic expression: ";
+    // std::getline(std::cin, infix);
+
+    std::cout << "e.g. 1 1+4*5" << std::endl;
+    infix = "1+4*5";
+    std::string postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    int result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    std::cout << "e.g. 2 (1+4)*5" << std::endl;
+    infix = "(1+4)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    std::cout << "e.g. 3 1+4-5" << std::endl;
+    infix = "1+4-5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    return 0;
+}

task2/temp/_draft/helloworld copy.cpp

@@ -0,0 +1,103 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+
+// Function to convert infix expression to postfix expression
+std::string infixToPostfix(const std::string &infix)
+{
+    std::stack<char> s;
+    std::string postfix;
+    std::map<char, int> precedence = {{'+', 1}, {'-', 1}, {'*', 2}, {'/', 2}, {'(', 0}};
+
+    for (char c : infix)
+    {
+        if (std::isalnum(c))
+        { // 1. if operand, add to postfix
+            postfix += c;
+        }
+        else if (c == '(')
+        { // 2. if '(', push to stack
+            s.push(c);
+        }
+        else if (c == ')')
+        { // 3. if ')', pop until '('
+            while (!s.empty() && s.top() != '(')
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            if (!s.empty())
+                s.pop(); // pop '('
+        }
+        else
+        { // 4. if operator, pop operators with greater or equal precedence
+            while (!s.empty() && precedence[c] <= precedence[s.top()])
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            s.push(c); // push current operator
+        }
+    }
+    // 5. pop remaining operators
+    while (!s.empty())
+    {
+        postfix += s.top();
+        s.pop();
+    }
+    return postfix;
+}
+
+// Function to evaluate postfix expression
+int evaluatePostfix(const std::string &postfix)
+{
+    std::stack<int> s;
+
+    for (char c : postfix)
+    {
+        if (std::isdigit(c))
+        { // 1. if operand, push to stack
+            s.push(c - '0');
+        }
+        else
+        { // 2. if operator, pop two operands, evaluate and push result
+            int op2 = s.top();
+            s.pop();
+            int op1 = s.top();
+            s.pop();
+            switch (c)
+            {
+            case '+':
+                s.push(op1 + op2);
+                break;
+            case '-':
+                s.push(op1 - op2);
+                break;
+            case '*':
+                s.push(op1 * op2);
+                break;
+            case '/':
+                s.push(op1 / op2);
+                break;
+            }
+        }
+    }
+    return s.top(); // 3. result is the only element in stack
+}
+
+int main()
+{
+    std::string infix;
+    std::cout << "Enter an arithmetic expression: ";
+    std::getline(std::cin, infix);
+
+    std::string postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    int result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    return 0;
+}

task2/temp/build.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+set -ex
+
+g++ -o output helloworld.cpp
+
+echo "build done"
+
+./output

task2/temp/helloworld.cpp

@@ -0,0 +1,185 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+
+// 2. pseudo code of the algorithm
+// convert to postfix expression use stack,
+// 1. if it is an operand, add to postfix,
+// 2. if it is an operator,
+//      2.1 if it is the first operator, push into `s` stack
+//      2.2 if `s` stack already got element, compare the weight of opreators
+//      2.3 pop `s` stack until the top most one got smaller precedence
+// 3. if it is a bracket, push into stack `s`,
+// 3. if it is a closing bracket, pop all element from `s` stack back to postfix,
+// else return the result
+
+// Function to convert infix expression to postfix expression
+std::string infixToPostfix(const std::string &infix)
+{
+    std::stack<char> s;
+    std::string postfix;
+    std::map<char, int> precedence = {{'+', 1}, {'-', 1}, {'*', 2}, {'/', 2}, {'(', 0}};
+
+    for (char c : infix)
+    {
+        if (std::isalnum(c))
+        { // 1. if operand, add to postfix
+            postfix += c;
+        }
+
+        // 其實括號入面同括號出面嘅數你當佢兩條式計就得
+        else if (c == '(')
+        { // 2. if '(', push to stack
+            s.push(c);
+        }
+
+        // 咁去呢度關括號呀嘛,
+        // 咁佢咪會由個 stack 嗰度 port 返曬啲operator出嚟囉, 變咗可以 14+5*
+        else if (c == ')')
+        { // 3. if ')', pop until '('
+            while (!s.empty() && s.top() != '(')
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            if (!s.empty())
+                s.pop(); // pop '('
+        }
+        else
+        { // 4. if operator, pop operators with greater or equal precedence
+            while (!s.empty() && precedence[c] <= precedence[s.top()])
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            s.push(c); // push current operator
+        }
+    }
+
+    // 5. pop remaining operators, LIFO
+    while (!s.empty())
+    {
+        postfix += s.top();
+        s.pop();
+    }
+
+    return postfix;
+}
+
+// Function to evaluate postfix expression
+
+// 2. pseudo code of the algorithm
+// evaluate a postfix expression use stack,
+// if it is an operand, push it into stack,
+// if it is an operator, pop the top two elements, apply the operator, and push the result,
+// if it is a bracket, pop until the matched bracket, then push it into stack,
+// if the input is end, return the last element in stack,
+// else error
+
+int evaluatePostfix(const std::string &postfix)
+{
+    std::stack<int> s;
+
+    for (char c : postfix)
+    {
+        if (std::isdigit(c))
+        { // 1. if operand, push to stack
+            s.push(c - '0');
+        }
+        else
+        { // 2. if operator, pop two operands, evaluate and push result
+            int op2 = s.top();
+            s.pop();
+            int op1 = s.top();
+            s.pop();
+            switch (c)
+            {
+            case '+':
+                s.push(op1 + op2);
+                break;
+            case '-':
+                s.push(op1 - op2);
+                break;
+            case '*':
+                s.push(op1 * op2);
+                break;
+            case '/':
+                s.push(op1 / op2);
+                break;
+            }
+        }
+    }
+    return s.top(); // 3. result is the only element in stack
+}
+
+int main()
+{
+    std::string infix;
+    // std::cout << "Enter an arithmetic expression: ";
+    // std::getline(std::cin, infix);
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+
+    // 1,20,+
+    // 21
+    std::cout << "e.g. 1 1+4*5" << std::endl;
+    infix = "1+4*5";
+    std::string postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    int result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,+,5,*
+    // 5,5,*
+    // 25
+    std::cout << "e.g. 2 (1+4)*5" << std::endl;
+    infix = "(1+4)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,+,5,-
+    // 5,5,-
+    // 0
+    std::cout << "e.g. 3 1+4-5" << std::endl;
+    infix = "1+4-5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+,5,*
+    // 1,20,+,5,*
+    // 21,5,*
+    // 105
+    std::cout << "e.g. 4 (1+4*5)*5" << std::endl;
+    infix = "(1+4*5)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+,2,5,*,-
+    // =>1,20,+,2,5,*,-
+    // =>21,2,5,*,-
+    // =>21,10,-
+    // =>11
+    std::cout << "e.g. 5 (1+4*5)-2*5" << std::endl;
+    infix = "(1+4*5)-2*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    return 0;
+}

task2/temp/main.cpp

@@ -0,0 +1,185 @@
+#include <iostream>
+#include <stack>
+#include <string>
+#include <cctype>
+#include <map>
+
+// 2. pseudo code of the algorithm
+// convert to postfix expression use stack,
+// 1. if it is an operand, add to postfix,
+// 2. if it is an operator,
+//      2.1 if it is the first operator, push into `s` stack
+//      2.2 if `s` stack already got element, compare the weight of opreators
+//      2.3 pop `s` stack until the top most one got smaller precedence
+// 3. if it is a bracket, push into stack `s`,
+// 3. if it is a closing bracket, pop all element from `s` stack back to postfix,
+// else return the result
+
+// Function to convert infix expression to postfix expression
+std::string infixToPostfix(const std::string &infix)
+{
+    std::stack<char> s;
+    std::string postfix;
+    std::map<char, int> precedence = {{'+', 1}, {'-', 1}, {'*', 2}, {'/', 2}, {'(', 0}};
+
+    for (char c : infix)
+    {
+        if (std::isalnum(c))
+        { // 1. if operand, add to postfix
+            postfix += c;
+        }
+
+        // 其實括號入面同括號出面嘅數你當佢兩條式計就得
+        else if (c == '(')
+        { // 2. if '(', push to stack
+            s.push(c);
+        }
+
+        // 咁佢呢度關括號呀嘛,
+        // 咁佢咪會由個 stack 嗰度 port 返曬啲operator出嚟囉, 變咗可以 14+5*
+        else if (c == ')')
+        { // 3. if ')', pop until '('
+            while (!s.empty() && s.top() != '(')
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            if (!s.empty())
+                s.pop(); // pop '('
+        }
+        else
+        { // 4. if operator, pop operators with greater or equal precedence
+            while (!s.empty() && precedence[c] <= precedence[s.top()])
+            {
+                postfix += s.top();
+                s.pop();
+            }
+            s.push(c); // push current operator
+        }
+    }
+
+    // 5. pop remaining operators, LIFO
+    while (!s.empty())
+    {
+        postfix += s.top();
+        s.pop();
+    }
+
+    return postfix;
+}
+
+// Function to evaluate postfix expression
+
+// 2. pseudo code of the algorithm
+// evaluate a postfix expression use stack,
+// if it is an operand, push it into stack,
+// if it is an operator, pop the top two elements, apply the operator, and push the result,
+// if it is a bracket, pop until the matched bracket, then push it into stack,
+// if the input is end, return the last element in stack,
+// else error
+
+int evaluatePostfix(const std::string &postfix)
+{
+    std::stack<int> s;
+
+    for (char c : postfix)
+    {
+        if (std::isdigit(c))
+        { // 1. if operand, push to stack
+            s.push(c - '0');
+        }
+        else
+        { // 2. if operator, pop two operands, evaluate and push result
+            int op2 = s.top();
+            s.pop();
+            int op1 = s.top();
+            s.pop();
+            switch (c)
+            {
+            case '+':
+                s.push(op1 + op2);
+                break;
+            case '-':
+                s.push(op1 - op2);
+                break;
+            case '*':
+                s.push(op1 * op2);
+                break;
+            case '/':
+                s.push(op1 / op2);
+                break;
+            }
+        }
+    }
+    return s.top(); // 3. result is the only element in stack
+}
+
+int main()
+{
+    std::string infix;
+    // std::cout << "Enter an arithmetic expression: ";
+    // std::getline(std::cin, infix);
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+
+    // 1,20,+
+    // 21
+    std::cout << "e.g. 1 1+4*5" << std::endl;
+    infix = "1+4*5";
+    std::string postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    int result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,+,5,*
+    // 5,5,*
+    // 25
+    std::cout << "e.g. 2 (1+4)*5" << std::endl;
+    infix = "(1+4)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,+,5,-
+    // 5,5,-
+    // 0
+    std::cout << "e.g. 3 1+4-5" << std::endl;
+    infix = "1+4-5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+,5,*
+    // 1,20,+,5,*
+    // 21,5,*
+    // 105
+    std::cout << "e.g. 4 (1+4*5)*5" << std::endl;
+    infix = "(1+4*5)*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    // --- part 2 iteration:
+    // 1,4,5,*,+,2,5,*,-
+    // =>1,20,+,2,5,*,-
+    // =>21,2,5,*,-
+    // =>21,10,-
+    // =>11
+    std::cout << "e.g. 5 (1+4*5)-2*5" << std::endl;
+    infix = "(1+4*5)-2*5";
+    postfix = infixToPostfix(infix);
+    std::cout << "Postfix expression: " << postfix << std::endl;
+
+    result = evaluatePostfix(postfix);
+    std::cout << "Result: " << result << std::endl;
+
+    return 0;
+}

task2/temp/prompt.md

@@ -0,0 +1,31 @@
+# Task
+I want you to write a simple calculator to evaluate arithmetic expressions.
+Solve your problem step by step with C++.
+Please consider the precedence of operators as well.
+
+## It includes two parts:
+
+- In the first part, you need to convert the input to a postfix expression.
+- In the second part, you need to evaluate the postfix expression that you get in the first
+  part.
+- You need to implement your algorithms using c++.
+- You also need to write comment inside the code explaining the following items.
+
+## Part 1: Convert an expression to postfix expression using stack in STL
+
+1. how to read and store the input?
+2. pseudo code of the algorithm
+3. data structures used in the algorithm
+4. time complexity
+5. space complexity
+6. how to store the postfix expression?
+
+## Part 2: Use stack of STL to evaluate a postfix expression
+
+1. how to read the postfix expression
+2. pseudo code of the algorithm
+3. data structures used in the algorithm
+4. time complexity
+5. space complexity
+6. how to output the final result?
+