update,

2025-01-31 19:15:17 +08:00
parent 09adae8c8e
commit 6c60a73f30
1546 changed files with 286918 additions and 0 deletions
--- a/_resources/it114105/itp3914/Lab10/README.md.original
+++ b/_resources/it114105/itp3914/Lab10/README.md.original
@@ -0,0 +1,241 @@
+# Lab 10 Objects and Classes
+## Topic 4.1 to 4.4 Part (a) Objects and Classes
+
+## Exercise 1
+
+(a) Create a class `Employee` that has
+
+Variables:
+| Instance Variable name | Data type |
+| - | - |
+| name | String | 
+| salary | int |
+
+Methods:`getName()`, `setName()`, `getSalary()` and `setSalary()`
+
+(b) Complete the following test program that creates two `Employee` object instances named `emp1` and `emp2`. Then perform the followings:
+1. Set the name and salary of `emp1` to *"Chan Tai Man"* and 12000, respectively.
+2. Set the name and salary of `emp2` to *"Tam Ping Shing"* and 13500, respectively.
+3. Print the current details of `emp1` and ``emp2``.
+4. Increase the salary of *"Chan Tai Man"* by 10% and the salary of *"Tam Ping Shing"* by 5%.
+5. Print the new details of `emp1` and `emp2`.
+
+```java
+public class Ex1b {
+
+  public static void main(String[] args) {
+
+    Employee emp1 = new Employee();
+    Employee emp2 = new Employee();
+    int oldSalary;
+
+    // Part 1-2 here
+    // Part 3 below
+    System.out.println("Before-");
+    System.out.println("Employee 1: name=" + emp1.getName() +" salary=" + emp1.getSalary());
+    System.out.println("Employee 2: name=" + emp2.getName() +" salary=" + emp2.getSalary());
+
+    // Part 4-5 here
+
+  }
+}
+```
+
+The output of the program is shown below.
+```
+C:\> java Ex1b
+
+Before-
+Employee 1: name=Chan Tai Man salary=12000
+Employee 2: name=Tam Ping Shing salary=13500
+After-
+Employee 1: name=Chan Tai Man salary=13200
+Employee 2: name=Tam Ping Shing salary=14175
+```
+
+(c) Redo Part (b) by adding a Constructor to set the name and salary.
+
+(d) Add a method `displayDetails()` to display the name and salary in Employee class, and modify Ex1b to use `displayDetails()`to print the details of `emp1` and `emp2`.
+
+(e) Add method `raiseSalary()` that accepts a percentage increase in salary (`double`) as argument and increases the salary by the corresponding percentage. Create a new Test program `Ex1cde.java` to raise Chan’s salary by 10% and that of Tam by 5%. Print the details of `emp1` and `emp2` after the increase of salaries.
+
+```
+C:\> java Ex1cde
+
+Before-
+Employee: name=Chan Tai Man salary=12000
+Employee: name=Tam Ping Shing salary=13500
+After-
+Employee: name=Chan Tai Man salary=13200
+Employee: name=Tam Ping Shing salary=14175
+```
+
+## Exercise 2
+(a) Create a class `Student` that has
+
+Variables:
+| Attribute name | Data type |
+| - | - |
+| name | String | 
+| id | int |
+| score | double |
+
+Methods: *the getter and setter methods for each of the above attributes.*
+
+
+(b) Write a test program Ex2b.java that creates three Student object instances named `stud1`, `stud2` and `stud3`. Then perform the followings:
+1. Set the name, id and score of stud1 to *"Cheung Siu Ming"*, 310567 and 87.1.
+2. Set the name, id and score of stud2 to *"Ng Wai Man"*, 451267 and 77.5.
+3. Set the name, id and score of stud3 to *"Wong Sui Kai"*, 789014 and 83.4.
+4. Print the details of `stud1`, `stud2` and `stud3`.
+5. Find and print the average score among the three students.
+
+The output of the program is shown below.
+```
+C:\> java Ex2b
+Student : name=Cheung Siu Ming id=310567 score=87.1
+Student : name=Ng Wai Man id=451267 score=77.5
+Student : name=Wong Sui Kai id=789014 score=83.4
+
+Average Score = 82.66666666666667
+```
+
+(c) Redo Part (b) by adding a Constructor to set the name, id and score and then create a new test program `Ex2c.java` to test it.
+
+```
+C:\> java Ex2c
+Student : name=Cheung Siu Ming id=310567 score=87.1
+Student : name=Ng Wai Man id=451267 score=77.5
+Student : name=Wong Sui Kai id=789014 score=83.4
+
+Average Score = 82.66666666666667
+```
+
+## Exercise 2
+Consider the following classes.
+
+```java
+class AStudent {
+  private String name;
+  public int age;
+
+  public void setName(String inName) {
+    name = inName;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+}
+
+public class Ex3 {
+
+  public static void main(String s[]) {
+    AStudent stud1 = new AStudent();
+    AStudent stud2 = new AStudent();
+    stud1.setName("Chan Tai Man");
+    stud1.age = 19;
+    stud2.setName("Ng Hing");
+    stud2.age = -23;
+    System.out.println("Student: name=" + stud1.getName() +", age=" + stud1.age);
+
+    System.out.println("Student: name=" + stud2.getName() +", age=" + stud2.age);
+
+  }
+}
+```
+
+For the object `stud2`, age is -23 which is a negative value, this is not allowed in human being.
+
+Enhance the class `AStudent` by enforcing data encapsulation on the attribute `age`. If the inputted `age` is invalid, print an error message and set the age to 18.
+
+```
+C:\> java Ex3
+-23 is not allowed! Age must be greater than or equal to 18!
+Student: name=Chan Tai Man, age=19
+Student: name=Ng Hing, age=18
+```
+
+## Exercise 4
+Given the following CurrencyConverter class which handles the exchange between a foreign currency and US dollars.
+```java
+public class CurrencyConverter {
+  private double exchangeRate;
+  private double commissionRate;
+  private int largeAmount;
+
+  public CurrencyConverter(double er, double cr) {
+    exchangeRate = er;
+    commissionRate = cr;
+  }
+
+  public double fromUSDollar(double dollar) {
+
+    if (dollar >= largeAmount)
+      return (dollar * exchangeRate * (1 - commissionRate * 0.5));
+    else
+      return (dollar * exchangeRate * (1 - commissionRate));
+
+  }
+
+  public double toUSDollar(double foreignMoney) {
+
+    if (foreignMoney / exchangeRate >= largeAmount)
+      return (foreignMoney / exchangeRate * (1 - commissionRate * 0.5));
+    else
+      return (foreignMoney / exchangeRate * (1 - commissionRate));
+
+  }
+
+  public void setExchangeRate(double rate) {
+    exchangeRate = rate;
+  }
+
+  public double getExchangeRate() {
+    return exchangeRate;
+  }
+
+  public void setCommissionRate(double rate) {
+    commissionRate = rate;
+  }
+
+  public double getCommissionRate() {
+    return commissionRate;
+  }
+
+  public void setLargeAmount(int amount) {
+    largeAmount = amount;
+  }
+
+  public int getLargeAmount() {
+    return largeAmount;
+  }
+}
+```
+
+Write a test program `Ex4.java` to test the CurrencyConverter class by performing the following operations:
+
+1. Instantiate two `CurrencyConverter` object with the following attributes:
+ 
+|  | exchangeRate | comissionRate |
+| - | - | - |
+| yenConverter | 115.7 | 0.0005 |
+| euroCOnverter | 0.9881 | 0.0003 |
+
+2. Set `largeAmount` to 50000.
+3. Use the `yenConverter` to convert 1500000 yens to US dollars.
+4. Use the `yenConverter` to convert from US$2000 to yens.
+5. Set the exchange rate of euro to 0.9881.
+6. Use the `euroConverter` to convert 170000 euros to US$.
+7. Use the `euroConverter` to convert from US$20000 to euros.
+
+Sample output
+```
+C:\> java Ex4
+1500000 yens = US$ 12958.0812445981
+US$ 2000 = 231284.30000000002 yens
+
+170000 euros = US$ 172021.55652261918
+US$ 20000 = 19756.0714 euros
+```