Java计算器程序中do while循环的执行

Question

In my Java Program, I have used a Boolean variable 'decision' which should execute the actual calculator code in the 'do loop code block' only when the variable is true, but the do while loop is executed anyways even when the decision variable is false. I am using Eclipse IDE for Java and JDK 10 (both are recent versions). Please help me with a solution. The code is as below

import java.util.Scanner;

public class apples {

public static void main(String[] args) {

    int option,a,b,c;
    boolean decision;
    System.out.println("We are here to create a calculator");
    System.out.print("Do you want to switch on the calculator:");
    Scanner yogi = new Scanner(System.in);
    decision = yogi.nextBoolean();
    do {
        System.out.println("Following operations are available to perform:");
        System.out.println("1. Addition");
        System.out.println("2. Subtraction");
        System.out.println("3. Multiplication");
        System.out.println("4. Division");
        System.out.print("Enter the operations do you want to perform:");
        option = yogi.nextInt();
        System.out.println("Choice of operation is:"+option);

        switch(option) {

        case 1:
            System.out.println("Enter two numbers to be added:");
            a = yogi.nextInt();
            b = yogi.nextInt();
            c = a + b;
            System.out.print("Addition:"+c);
            break;

        case 2:
            System.out.println("Enter two numbers to be subtracted:");
            a = yogi.nextInt();
            b = yogi.nextInt();
            c = a - b;
            System.out.print("subtracted:"+c);
            break;

        case 3:
            System.out.println("Enter two numbers to be multiplied:");
            a = yogi.nextInt();
            b = yogi.nextInt();
            c = a * b;
            System.out.print("multiplied:"+c);
            break;

        case 4:
            System.out.println("Enter two numbers to be divided:");
            a = yogi.nextInt();
            b = yogi.nextInt();
            c = a / b;
            System.out.print("divided:"+c);
            break;

        default:
            System.out.println("This is a wrong choice");
            break;
        }
    }while(decision==true);
  }
}

Answer 1

the do while loop is executed anyways even when the decision variable is false

A do...while will executes the body once before checking the condition.

Either modify your code for while or add an if-else enclosing do...while .

Answer 2

You can add another case 5 and in that write System.exit(0) for the successful termination of the program.

In the while part pass (option != 5) . This should run the program. You don't need decision variable.