Calculator.java

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // Take input from user till user does not press X or x
        int ans = 0;
        while (true) {
            // take the operator as input
            System.out.print("Enter the operator: ");
            char op = in.next().trim().charAt(0);

            if (op == '+' || op == '-' || op == '*' || op == '/' || op == '%') {
                // input two numbers
                System.out.print("Enter two numbers: ");
                int num1 = in.nextInt();
                int num2 = in.nextInt();
                switch (op) {
                    case '+':
                        ans = num1 + num2;
                        break;
                    case '-':
                        ans = num1 - num2;
                        break;
                    case '*':
                        ans = num1 * num2;
                        break;
                    case '/':
                        ans = num1 / num2;
                        break;
                    case '%':
                        ans = num1 / num2;
                        break;
                }
            } else if (op == 'x' || op == 'X') {
                break;
            } else {
                System.out.println("Invalid operation!!");
            }
            System.out.println(ans);
        }
        in.close();
    }
}