How to Build Simple Calculator Program in Java?

                         

In This Program, The User Is Prompted To Enter The First Number, An Operator (+, -, *, Or /), And The Second Number. The Program Then Performs The Corresponding Arithmetic Operation And Displays The Result. It Also Handles The Case Of Division By Zero.

You Can Compile And Run This Program In Any Java Development Environment Or By Using The Command Line.

import java.util.Scanner;

public class Calculator {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        double num1, num2, result;

        char operator;

        System.out.print("Enter the first number: ");

        num1 = scanner.nextDouble();

        System.out.print("Enter an operator (+, -, *, /): ");

        operator = scanner.next().charAt(0);

        System.out.print("Enter the second number: ");

        num2 = scanner.nextDouble();

        switch (operator) {

            case '+':

                result = num1 + num2;

                System.out.println("Result: " + result);

                break;

            case '-':

                result = num1 - num2;

                System.out.println("Result: " + result);

                break;

            case '*':

                result = num1 * num2;

                System.out.println("Result: " + result);

                break;

            case '/':

                if (num2 != 0) {

                    result = num1 / num2;

                    System.out.println("Result: " + result);

                } else {

                    System.out.println("Error: Division by zero is not allowed.");

                }

                break;

            default:

                System.out.println("Error: Invalid operator.");

                break;

        }

    }

}