Why doesn't my 'if' statement exit the do-while loop and if my 'catch' statement is executed, why doesn't it take input?

Question

Question 1: If an int greater or equal to 2 is entered by the user the first if statement becomes true and the code is executed setting the boolean error1 variable to false. The do loop should only repeat if the error1 variable is true according to my while statement. However the loop repeats regardless.

How can I make the first if statement when set to true exit the loop?

Question 2: I am using a try-catch code to help repeat the the do-while loop if anything other than an int is entered by the user. However, when something like abc or 12.3 is entered the first println of the try code is executed, the second line of the try statement asking for user input is ignored and the catch code is executed again. This becomes a non-terminating loop without user input.

How can I get the statement to ask for user input after the catch code is executed?

Here is my code:

import java.util.InputMismatchException;
import java.util.Scanner;

public class DeepbotCalc {

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);

    int points = 0;
    boolean error1 = false;

    do {
        try {
            System.out.println("How many points do you currently have?");
            points = input.nextInt();

            if (points >= 2){
                error1 = false;
            }

            else if (points > 0 && points < 2) {
                System.out.println("you need at least 2 points");
                error1 = true;
            }

            else if (points <= 0) {
                System.out.println("Please enter a positive whole number");
                error1 = true;
            }
        } catch (InputMismatchException e){
            System.out.println("Please enter a positive whole number.");
            error1 = true;
        }
    } while (error1 = true);

Dido what @SotiriosDelimanolis said. How will future readers make sense of the answer/solution. — Michael Markidis, Jun 20 '16 at 22:01
Never edit your question overriding the original code with your solution. If you want to add the solution, you can do it at the end as an update to the question. And remember to always format everything that is part of your code, not using apostrophes. — SpaceCore186, Jun 20 '16 at 22:05
I added the solution to my question so future readers won't answer the same part of the question multiple times. In the future I won't do this. I'll also use proper formatting when talking about my code. — Curse_USMC, Jun 20 '16 at 22:30

Loris Securo · Answer 1 · 2016-06-20T22:10:15.110

0

To stop the loop when the correct input is inserted,

while (error1 = true);

should become

while (error1 == true);

or even better

while(error1);

To fix the endless loop when the incorrect input is inserted, inside the catch add

input.nextLine();

to let the scanner "move on"

edited Jun 20 '16 at 22:10

answered Jun 20 '16 at 21:45

Loris Securo

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Thanks I was unaware that just putting a Boolean variable in at statement would test it but I guess it makes sense. – Curse_USMC Jun 20 '16 at 21:49
The endless loop without user input still occurs when the catch statement is executed though. – Curse_USMC Jun 20 '16 at 21:51
Edited for the endless loop – Loris Securo Jun 20 '16 at 21:55
That repeated the loop while asking for user input each time until a valid input. Thank you. This answered my question. – Curse_USMC Jun 20 '16 at 22:01

score 0 · Accepted Answer · answered Jun 20 '16 at 21:58

This solves your problem:

import java.util.InputMismatchException;
import java.util.Scanner;

public class DeepbotCalc {

    public static void main(String[] args) {
        Scanner input;

        int points = 0;
        boolean error1 = false;

        do {

            try {
                input = new Scanner(System.in);
                System.out.println("How many points do you currently have?");
                points = input.nextInt();


                if (points >= 2) {
                    error1 = false;
                }

                else if (points > 0 && points < 2) {
                    System.out.println("you need at least 2 points");
                    error1 = true;
                }

                else if (points <= 0) {
                    System.out.println("Please enter a positive whole number");
                    error1 = true;
                }

            }

            catch (InputMismatchException e) {
                System.out.println("Please enter a positive whole number.");
                error1 = true;
            }

        } while (error1);
    }
}

I changed while(error1 = true) by while(error1), and added a new line of code in the try{} statement.

Each time the try{} statement is executed, a new Scanner object is created overriding the last one.

Why doesn't my 'if' statement exit the do-while loop and if my 'catch' statement is executed, why doesn't it take input?

2 Answers2