如何使程序继续执行代码而不再次打印它

Question

I have this code:

public void checkUserLuckyNumber(PC p, User u) {
    int userLuckyNumber = Integer.parseInt(JOptionPane.showInputDialog(null, "Input lucky number from 1 - 10:"));
    if (userLuckyNumber < 1 || userLuckyNumber > 10) {
        JOptionPane.showMessageDialog(null, Constants.INVALIDINPUTNUMBER);
        System.exit(0);
    }
    for (int i = 1; i <= 3; i++) {
        int threeLuckyNumbers = (int) (Math.random() * 10);

        if (userLuckyNumber == threeLuckyNumbers) {
            JOptionPane.showMessageDialog(null, "you hit a happy number");
        } else {
            JOptionPane.showMessageDialog(null, "you did not hit a lucky number");
        }
    }
}
}

My problem is that my program print me three time message, if user hit lucky number program print me one message "you hit a happy number" and if user miss lucky number, program print me one message "you hit a happy number" and then twice " you did not hit a lucky number".

So my question is how to make program that print just one message.

Answer 1

Try using break in your for loop, for the success case:

for (int i = 1; i <= 3; i++) {
    int threeLuckyNumbers = (int) (Math.random() * 10);

    if (userLuckyNumber == threeLuckyNumbers) {
        JOptionPane.showMessageDialog(null, "you hit a happy number");
        break; // I added this
    } else {
        JOptionPane.showMessageDialog(null, "you did not hit a lucky number");
        break;
    }
}

The break keyword is used for control flow in Java code. In the above case, when used inside the for loop it terminates that loop, and the code continues with whatever follows immediately after the end of the loop.

Answer 2

break the loop as soon as luck number is hit!

    for (int i = 1; i <= 3; i++) {
     int threeLuckyNumbers = (int)(Math.random() * 10);

     if (userLuckyNumber == threeLuckyNumbers) {
      JOptionPane.showMessageDialog(null, "you hit a happy number");
     } else {
      JOptionPane.showMessageDialog(null, "you did not hit a lucky number");
     }

      break;
    }

Break once as soon as you determine the hit or miss. But then you should not be looping 3 times at first place.