1  import java.util.Scanner;
  2  
  3  public class SubtractionQuizLoop {
  4    public static void main(String[] args) {
  5      final int NUMBER_OF_QUESTIONS = 5; // Number of questions
  6      int correctCount = 0; // Count the number of correct answers
  7      int count = 0; // Count the number of questions
  8      long startTime = System.currentTimeMillis();
  9      String output = ""; // output string is initially empty
 10      Scanner input = new Scanner(System.in);
 11      
 12      while (count < NUMBER_OF_QUESTIONS) {
 13        // 1. Generate two random single-digit integers
 14        int number1 = (int)(Math.random() * 10);
 15        int number2 = (int)(Math.random() * 10);
 16  
 17        // 2. If number1 < number2, swap number1 with number2
 18        if (number1 < number2) {
 19          int temp = number1;
 20          number1 = number2;
 21          number2 = temp;
 22        }
 23  
 24        // 3. Prompt the student to answer "What is number1 – number2?"
 25        System.out.print(
 26          "What is " + number1 + " - " + number2 + "? ");
 27        int answer = input.nextInt();
 28  
 29        // 4. Grade the answer and display the result
 30        if (number1 - number2 == answer) {
 31          System.out.println("You are correct!\n");
 32          correctCount++;
 33        }
 34        else
 35          System.out.println("Your answer is wrong.\n" + number1 
 36            + " - " + number2 + " should be " + (number1 - number2) + "\n");
 37  
 38        // Increase the count
 39        count++;
 40  
 41        output += "\n" + number1 + "-" + number2 + "=" + answer + 
 42          ((number1 - number2 == answer) ? " correct" : " wrong");
 43      }
 44  
 45      long endTime = System.currentTimeMillis();
 46      long testTime = endTime - startTime;
 47  
 48      System.out.println("Correct count is " + correctCount + 
 49        "\nTest time is " + testTime / 1000 + " seconds\n" + output);
 50    }
 51  }