Help....need help closing a while loop & getting input q from user to quit program?

If you want to allow the user to choose when to quit, you don't want to have an infiniate while loop that's always true. The way to do it is to prompt for your first input outside of the while loop, informing the user to enter in some large or small number as an exit condition. Then your while condition will be to check if it's equal to that exit condition or not. If it's not, then prompt for the other three inputs, do the math, output the display, then reprompt for that first number again before the end of the while loop. Then if they enter the exit condition, when it goes to the top of the while, it's checked and program ends. otherwise goes back in to the loop for the other three values . Here's an example: Scanner input = new Scanner(System.in); // Prompt for input outside of while loop, then again before loop ends System.out.print("Enter x1 and y1 (Enter -99999 for x1 to quit): "); double x1 = input.nextDouble(); while (x1 != -99999) { double y1 = input.nextDouble(); // Enter the first point with two values System.out.print("Enter x2 and y2: "); double x2 = input.nextDouble(); double y2 = input.nextDouble(); // Compute the distance double distance = Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)); distance = Math.round(distance * 100.0) / 100.0; JOptionPane.showMessageDialog(null, "The distance of the two points is " + distance); // Reprompt for input so while condition can be rechecked for exit condition System.out.print("Enter x1 and y1 (Enter -99999 for x1 to quit): "); double x1 = input.nextDouble(); } // while loop