1. Introduction

In this tutorial, we will develop a simple calculator in Java that can perform basic arithmetic operations like addition, subtraction, multiplication, and division.

2. Program Steps

1. Define a class named SimpleCalculator.

2. In the main method of the class, use Scanner to take user input.

3. Display a menu to the user to select the operation.

4. Take the user’s choice and perform the corresponding operation.

5. Display the result of the operation.

3. Code Program

import java.util.Scanner; // Import Scanner class

public class SimpleCalculator { // Step 1: Define a class named SimpleCalculator

    public static void main(String[] args) { // Main method

        Scanner scanner = new Scanner(System.in); // Step 2: Use Scanner to take user input

        System.out.println("Simple Calculator");
        System.out.println("1. Add");
        System.out.println("2. Subtract");
        System.out.println("3. Multiply");
        System.out.println("4. Divide");
        System.out.print("Enter choice (1/2/3/4): "); // Step 3: Display a menu to the user

        int choice = scanner.nextInt(); // Take user's choice

        System.out.print("Enter first number: ");
        double num1 = scanner.nextDouble();
        System.out.print("Enter second number: ");
        double num2 = scanner.nextDouble();

        double result = 0;

        // Step 4: Perform the corresponding operation
        switch(choice) {
            case 1:
                result = num1 + num2;
                break;
            case 2:
                result = num1 - num2;
                break;
            case 3:
                result = num1 * num2;
                break;
            case 4:
                result = num1 / num2;
                break;
            default:
                System.out.println("Invalid choice");
                break;
        }

        // Step 5: Display the result of the operation
        System.out.println("Result: " + result);

        scanner.close(); // Close the Scanner
    }
}

Output:

Simple Calculator
1. Add
2. Subtract
3. Multiply
4. Divide
Enter choice (1/2/3/4): 1
Enter first number: 5
Enter second number: 3
Result: 8.0

4. Step By Step Explanation

– Step 1: The SimpleCalculator class is defined.

– Step 2: A Scanner object is created to take user input.

– Step 3: A menu is displayed to the user, prompting them to select an operation.

– Step 4: Depending on the user's choice, the corresponding arithmetic operation is performed using a switch case.

– Step 5: The result of the operation is displayed to the user.