Java-While循环不会退出

Question

//Loop that isn't working. I keep pressing a number that is 1,2,3,4, or 5 but it won't exit the loop. The operator seems to be assigned the value that I input but it still will not exit the while loop. I'm trying to write a basic calculator with simple math operations but this turned into a very annoying problem.

import java.util.Scanner;
public class BasicCalculatorTwo {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int operator;
        double fnum, snum, answer;
        operator = 0;

        System.out.println("Enter first number : ");
        fnum = scanner.nextDouble();
        System.out.println("Enter second number : ");
        snum = scanner.nextDouble();

        while(operator != 1 || operator != 2 || operator != 3 || operator != 4 || operator != 5 ){
            System.out.println();
            System.out.println(fnum + " ? " + snum + " = ");
            System.out.println("1 : Add");
            System.out.println("2 : Subtract");
            System.out.println("3 : Multiply");
            System.out.println("4 : Divide");
            System.out.println("5 : Modularize");
            operator = scanner.nextInt();
        }

        switch(operator){
            case 1:
                answer = fnum + snum;
                break;
            case 2:
                answer = fnum - snum;
                break;
            case 3:
                answer = fnum * snum;
                break;
            case 4:
                answer = fnum / snum;
                break;
            case 5:
                answer = fnum % snum;
                break;
            default:
                break;
            System.out.println(fnum + " ? " + snum + " = " + answer);
            scanner.close();
        }
    }
}

Answer 1

You loop conditional is the problem.

while (operator != 1 || operator != 2 || operator != 3 || operator != 4 || operator != 5)

It should be

while (operator != 1 && operator != 2 && operator != 3 && operator != 4 && operator != 5)

Basically, you're saying that if the operator is != 1, then do the loop. Likewise each of the others. If you were to utilize && operators instead of || it would work much better.

Really, what you want to say is that operator is > 1 && < 5, then loop, otherwise break.

while(operator < 1 || operator > 5)
{
  DoPrintStuffHere();
}

Think about it logically, you want any number less than 1 OR greater than 5 to loop again.