A class of ten students took a quiz. The grade (integers in the range of 0 to 100) for this quiz are available to you. Determine the class average on the quiz.

Set total to zero
Set grade counter to one

While grade counter is less than or equal to ten
Input the next grade
Add the grade into the total
Add one to the grade counter

Set the class average to the total divided by ten
Print the class average

// Fig. 4.7: Average1.java
// Class-average program with counter-controlled repetition.
import javax.swing.JOptionPane;

public class Average1 {

   public static void main( String args[] ) 
   {
      int total;          // sum of grades input by user
      int gradeCounter;   // number of grade to be entered next
      int grade;          // grade value
      int average;        // average of grades

      String gradeString; // grade typed by user
   
      // initialization phase
      total = 0;          // initialize total
      gradeCounter = 1;   // initialize loop counter
   
      // processing phase
      while ( gradeCounter <= 10 ) {  // loop 10 times

         // prompt for input and read grade from user
         gradeString = JOptionPane.showInputDialog( 
            "Enter integer grade: " );

         // convert gradeString to int
         grade = Integer.parseInt( gradeString );

         total = total + grade;            // add grade to total
         gradeCounter = gradeCounter + 1;  // increment counter

      } // end while
   
      // termination phase
      average = total / 10;  // integer division

      // display average of exam grades
      JOptionPane.showMessageDialog( null, "Class average is " + average, 
         "Class Average", JOptionPane.INFORMATION_MESSAGE );

      System.exit( 0 );  // terminate the program

   } // end main

} // end class Average1

// Fig. 4.9: Average2.java
// Class-average program with sentinel-controlled repetition.
import java.text.DecimalFormat;  // class to format numbers
import javax.swing.JOptionPane;

public class Average2 {

   public static void main( String args[] )
   {
      int total;           // sum of grades
      int gradeCounter;    // number of grades entered
      int grade;           // grade value

      double average;  // number with decimal point for average

      String gradeString;  // grade typed by user

      // initialization phase
      total = 0;         // initialize total
      gradeCounter = 0;  // initialize loop counter
      
      // processing phase
      // get first grade from user
      gradeString = JOptionPane.showInputDialog(
         "Enter Integer Grade or -1 to Quit:" );

      // convert gradeString to int
      grade = Integer.parseInt( gradeString );

      // loop until sentinel value read from user
      while ( grade != -1 ) {  
         total = total + grade;            // add grade to total
         gradeCounter = gradeCounter + 1;  // increment counter

         // get next grade from user
         gradeString = JOptionPane.showInputDialog(
            "Enter Integer Grade or -1 to Quit:" );

         // convert gradeString to int
         grade = Integer.parseInt( gradeString );

      } // end while

      // termination phase
      DecimalFormat twoDigits = new DecimalFormat( "0.00" );

      // if user entered at least one grade...
      if ( gradeCounter != 0 ) {

         // calculate average of all grades entered
         average = (double) total / gradeCounter;  

         // display average with two digits of precision
         JOptionPane.showMessageDialog( null, 
            "Class average is " + twoDigits.format( average ), 
            "Class Average", JOptionPane.INFORMATION_MESSAGE );

      } // end if part of if...else

      else // if no grades entered, output appropriate message
         JOptionPane.showMessageDialog( null, "No grades were entered", 
            "Class Average", JOptionPane.INFORMATION_MESSAGE );

      System.exit( 0 );  // terminate application

   } // end main

} // end class Average2

// Fig. 4.11: Analysis.java
// Analysis of examination results.
import javax.swing.JOptionPane;

public class Analysis {

   public static void main( String args[] ) 
   {
      // initializing variables in declarations
      int passes = 0;          // number of passes
      int failures = 0;        // number of failures
      int studentCounter = 1;  // student counter
      int result;              // one exam result

      String input;            // user-entered value
      String output;           // output string

      // process 10 students using counter-controlled loop
      while ( studentCounter <= 10 ) {

         // prompt user for input and obtain value from user
         input = JOptionPane.showInputDialog(
            "Enter result (1 = pass, 2 = fail)" );

         // convert result to int
         result = Integer.parseInt( input );

         // if result 1, increment passes; if...else nested in while
         if ( result == 1 )
            passes = passes + 1;

         else // if result not 1, increment failures
            failures = failures + 1;

         // increment studentCounter so loop eventually terminates
         studentCounter = studentCounter + 1;  

      } // end while

      // termination phase; prepare and display results
      output = "Passed: " + passes + "\nFailed: " + failures;

      // determine whether more than 8 students passed
      if ( passes > 8 )
         output = output + "\nRaise Tuition";

      JOptionPane.showMessageDialog( null, output, 
         "Analysis of Examination Results", 
         JOptionPane.INFORMATION_MESSAGE );
      
      System.exit( 0 );  // terminate application

   } // end main

} // end class Analysis