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Thread: Issue with while loops...beginner question

  1. #1
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    Default Issue with while loops...beginner question

    This problem is inputting 10 numbers, and printing th My solution is working except it runs forever when I input anything other than an int. Can someon tell me whatI've done wrong?



    package com.company;
     
    import java.util.Scanner;
     
    public class Main {
     
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);
     
            int count = 1;
            int sum = 0;
            while (count<=10) {
                System.out.println("Enter number #"+count);
                boolean hasNextInt = scanner.hasNextInt();
     
                if (hasNextInt){
                    int number = scanner.nextInt();
                    count++;
                    sum +=number;
     
                }
     
                else {
                    System.out.println("Invalid Input");
                    continue;
                }
                scanner.nextLine();
     
     
            }System.out.println("the sum of these numbers is "+sum);
            scanner.close();
        }
    }

  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Issue with while loops...beginner question

    it runs forever
    Look at the condition that will end the loop. When is the value of count changed?

    If the Scanner has an invalid value (say hasNext... is false), it will keep that value until some next method reads and clears it.
    Be sure the code reads and rejects any invalid value before trying to read and process the next user input.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Issue with while loops...beginner question

    Quote Originally Posted by Norm View Post
    Look at the condition that will end the loop. When is the value of count changed?

    If the Scanner has an invalid value (say hasNext... is false), it will keep that value until some next method reads and clears it.
    Be sure the code reads and rejects any invalid value before trying to read and process the next user input.
    well I thought about it and I think removing the "continue;" fixes the issue

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Issue with while loops...beginner question

    Yes, that should work. Except for the case that the user has entered more than one number on a line before hitting Enter. But the current code already has that problem so there wouldn't be any change for the user.
    If you don't understand my answer, don't ignore it, ask a question.

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