Multiple conditions in WHILE loop

Question

I want to exit the while loop when the user enters 'N' or 'n'. But it does not work. It works well with one condition but not two.

import java.util.Scanner;

class Realtor {

    public static void main (String args[]){

        Scanner sc = new Scanner(System.in);

        char myChar = 'i';

        while(myChar != 'n' || myChar != 'N'){

           System.out.println("Do you want see houses today?");
           String input = sc.next();
           myChar = input.charAt(0); 
           System.out.println("You entered "+myChar);
        }
    }
}

Nick Rolando · Accepted Answer · 2012-06-11 23:58:32Z

25

You need to change || to && so that both conditions must be true to enter the loop.

while(myChar != 'n' && myChar != 'N')

answered Jun 11, 2012 at 23:58

Nick Rolando

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5 Comments

LINEMAN78 Over a year ago

You should also change it to a do-while loop so that you don't have to randomly initialize myChar.

Nick Rolando Over a year ago

Yeah, should definitely be a do-while

LINEMAN78 Over a year ago

You can also do Character.toLowerCase(myChar) != 'n' to make it more readable.

user547453 Over a year ago

this solved my problem. However, && means 'and'. This would mean both conditions have to be true. I am a PL-SQL developer and I find it difficult to understand this concept.

Nick Rolando Over a year ago

@user547453 If you use || then just one or the other condition can be true to enter the loop. If myChar = 'n' then myChar != 'n' is false, but myChar != 'N' is true, so it enters the loop. With && since the first condition would be false, it would not enter the loop.

toniedzwiedz · Accepted Answer · 2012-06-11 23:58:59Z

1

Your condition is wrong. myChar != 'n' || myChar != 'N' will always be true.

Use myChar != 'n' && myChar != 'N' instead

answered Jun 11, 2012 at 23:58

toniedzwiedz

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Comments

Edwin Dalorzo · Accepted Answer · 2012-06-12 00:00:14Z

0

If your code, if the user enters 'X' (for instance), when you reach the while condition evaluation it will determine that 'X' is differente from 'n' (nChar != 'n') which will make your loop condition true and execute the code inside of your loop. The second condition is not even evaluated.

answered Jun 12, 2012 at 0:00

Edwin Dalorzo

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