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/*P3Q1
 * Name:Wang Chaoran
 * Description:1 (Repeating subtractions)
Listing 4.1, SubtractionTutorLoop.java, generates ten random subtraction questions.
Revise the program to generate ten random addition questions for two integers between 1 and 15.
Display the number of correct answers and test time.
*/
import java.util.Scanner;
public class P3Q1 {
    public static void main(String[] args) { 
      int correctCount = 0; // Count the number of correct answers
      int count = 0; // Count the number of questions
      long startTime = System.currentTimeMillis();
      String output = "";
     
      while (count < 10) {
// 1. Generate two random single-digit integers
        int number1 = (int)(Math.random() * 15);
      int number2 = (int)(Math.random() * 15);
     
// 2. If number1 < number2, swap number1 with number2
      if (number1 < number2) {
        int temp = number1;
        number1 = number2;
        number2 = temp;
      }
// 3. Prompt the student to answer "what is number1 – number2?"
      Scanner scan = new Scanner(System.in);
      System.out.print("What is " + number1 + " + " + number2 + "?");
      int answer = scan.nextInt();
// 4. Grade the answer and display the result
      String replyString;
      if (number1 + number2 == answer) {
        replyString = "You are correct!";
        correctCount++;
      }      
      else        
        replyString = "Your answer is wrong.\n" + number1 + " + "+ number2 + " should be " + (number1 + number2);
             System.out.println(replyString);
// Increase the count      
             count++;
             output += "\n" + number1 + "+" + number2 + "=" + answer +
               ((number1 + number2 == answer) ? " correct" : " wrong");
      }
      long endTime = System.currentTimeMillis();
      long testTime = endTime - startTime;
      System.out.println("Correct count is " + correctCount + "\nTest time is " +
                         testTime / 1000 + " seconds\n" + output);
    }
}