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+# Lab 7 Repetition Part 1
+## Topic 3: Basic Program Structures
+
+### Intended Learning Outcomes
+Upon completion of this tutorial/lab, you should be able to:
+- Use loops to perform searching on a text string.
+- Use different types of loops to calculate sum of series.
+
+## Exercise 1
+Determine the output of the following Java programs.
+
+(a)
+```java
+public static void main( String[] args ) {
+   double balance = 1000;      // initialize to $1000
+   double interestRate = 0.1;
+   int years = 0;               // number of years
+   do {
+      balance = ( 1 + interestRate ) * balance;
+      years += 1;
+   } while ( balance <= 1200 );
+   System.out.println( years );
+}
+
+// Output:
+2
+```
+
+(b)
+```java
+public static void main( String[] args ) {
+   int j = 2;
+   String s = "";
+   while ( j <= 8 ) {
+      s += "*";
+      j += 2;
+   }
+   System.out.println( j + " " + s );
+}
+
+// Output:
+10 ****
+```
+(c)
+```java
+public static void main( String[] args ) {
+   int i;
+   for ( i=-9; i<=-1; i+=3 )
+      System.out.print( i + " " );
+}
+
+// Output:
+-9 -6 -3
+```
+
+## Exercise 2
+
+Identify and correct the error(s) in the program fragment below.
+
+(a)
+```java
+int c=0, product=1;
+while (c <= 5) {
+	product *= c;
+	++c;
+
+```
+Logic error:
+The variable product is always 0 after each loop, thus the loop is having no use.
+Having a syntactically correct program doesn't mean that your program is producing the
+correct result.
+
+(b)
+```java
+int x=1, total;
+While (x <= 10) {
+	total += x;
+	x++;
+}
+```
+Syntax error: While should be while.  
+Better: Although Java initializes numerical variables to 0 automatically if an initial value is
+not specified during variable declaration, it is better to write explicitly total=0 for better
+program readability.
+
+(c)
+```java
+For (int x=100, x >= 1, x++);
+	System.out.println(x);
+```
+Syntax error: for (int x=100; x >= 1; x++)  
+Logic error: x will always be greater than 1 and the loop will never terminate.
+Having a syntactically correct program doesn&#39;t mean that your program is producing the
+correct result.
+
+## Exercise 3
+What will be the value of variable $x$ after executing the following program fragment?
+
+```java
+int x=1, y=9;
+for (int i=0; i<y; i+=3)
+    x++;
+
+# x is 4
+```
+
+## Exercise 4
+What will be printed by the program fragments below?
+
+(a)
+```java
+int x=12;
+do {
+	System.out.print(x + " ");
+	x--;
+} while (x > 7);
+
+// Output:
+12 11 10 9 8
+```
+
+(b)
+```java
+for (int i=10; i<=25; i+=5)
+	System.out.print( (i/5) + " ")
+
+// Output:
+2 3 4 5
+```
+
+## Exercise 5
+What will be printed by the program below?
+
+```java
+public class Question {
+	public static void main(String [] args) {
+		int y, x=1, total=0;
+		while (x <= 5) {
+			y = x * x;
+			System.out.println(y);
+			total += y;
+			x++;
+		}
+		System.out.println("Total is " + total);
+	}
+}
+
+// Output:
+1
+4
+9
+16
+25
+Total is 55
+```
+
+## Exercise 6
+Rewrite the following programs with while loops.
+
+(a)
+```java
+public static void main( String[] args ) {
+   int i; 
+   for ( i=-9; i<=-1; i+=3 )
+      System.out.println( i ); 
+   System.out.println( "After loop, i=" + i );
+}
+```
+
+(b)
+```java
+public static void main( String[] args ) { 
+   int i = 5; 
+   do { 
+      System.out.println(i--); 
+   } while ( i >= 0 ); 
+   System.out.println( "After loop, i=" + i ); }
+```
+
+## Exercise 7
+Write a program to ask the user to input an int value. The program then prints the corresponding number of ‘*’ on screen.
+
+Shown below are two sample executions of the program. Those in underline are user inputs.
+
+```
+e:\> java Ex7
+Number of stars? _5_
+****
+```
+
+```
+e:\> java Ex7
+Number of stars? _9_
+*********
+```
+
+## Exercise 8
+Write a program to calculate n! where n is an integer value entered by the user.
+
+NOTE: $n! = n  (n-1) \times (n-2) \times (n-3) \times …\times 1$
+
+For example, $5!=5\times 5\times 4\times 3\times 2\times 1$
+
+Shown below are two sample executions of the program. Those in __ are user inputs.
+
+```
+e:\> java Ex8
+n? _3_
+3! = 6
+```
+
+```
+e:\> java Ex8
+n? _6_
+6! = 720
+```
+
+## Exercise 9
+Rewrite your program in Exercise 8 so that the output becomes:
+
+```
+e:\> java Ex9
+n? _3_
+3 x 2 x 1 = 6
+```
+
+```
+e:\> java Ex9
+n? _6_
+6 x 5 x 4 x 3 x 2 x 1 = 720
+```
+
+## Exercise 10
+Write a program to perform the followings:
+- Ask the user the number of values to enter
+- Read the values from the user
+- Calculate and print the average of the values.
+  
+Shown below is a sample execution of the program. Those in __ are user inputs.
+
+```
+e:\> java Ex10
+How many values to enter? _4_
+Value? _10_
+Value? _24_
+Value? _20_
+Value? _9_
+Average = 15.75
+```