Question

I am writing a simple program to calculate the average of a set of numbers. You get the numbers using Scanner, so I am using while loop with .hasNext() as a condition. However the loop is infinite.

Is it possible to break out of it without writing some certain word like “stop” in the input?

public class main {

    public static void main(String[] args){

        Scanner Input = new Scanner(System.in);
        int count = 0;
        int temp;
        int sum = 0;

        while(Input.hasNextInt()){

           count++;           

           temp = Input.nextInt();
           sum += temp;
           System.out.println(temp);
           System.out.println(count);           

        } // End of while

        double average = sum / count;
        System.out.println("The average is: " + average);

    } // End of method main

}

Answer 1

The break; statement can be sued to… well… break out of an iteration. And by iteration I mean you can get out of a for too, for example.

You have to define WHEN do you want to break out of the iteration and then do something like this:

while(Input.hasNextInt(Input)){
   if(condition())
       break;

   count++;           

   temp = Input.nextInt();
   sum += temp;
   System.out.println(temp);
   System.out.println(count);           

 }

Otherwise, you can make an auxiliary method that defines if the iteration should keep on going, like this one:

private boolean keepIterating(Scanner in) {
    boolean someOtherCondition = //define your value here that must evaluate to false
                                 //when you want to stop looping
    return Input.hasNextInt() && someOtherCondition;
}

Method that you will have to invoke in your while:

while(keepIterating()){

   count++;           

   temp = Input.nextInt();
   sum += temp;
   System.out.println(temp);
   System.out.println(count);           

}