Create a Simple Calculator Program in Java

How to Create a Calculator Java Program

In this tutorial, we will learn how to create a simple calculator program in Java. This program will be able to perform basic arithmetic operations such as addition, subtraction, multiplication, and division.

Step 1: Setting up the Project

Create a new Java project in your preferred IDE (Integrated Development Environment).
Create a new class called Calculator and make sure it has a main method.

Step 2: Designing the User Interface

We will use the Java Scanner class to get user input.
We will use System.out.println() to display the output.

Step 3: Writing the Code

Here is the code for the Calculator class:

Java

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("Enter the first number:");
        double num1 = scanner.nextDouble();

        System.out.println("Enter the operator (+, -, \*, /):");
        String operator = scanner.next();

        System.out.println("Enter the second number:");
        double num2 = scanner.nextDouble();

        double result = 0;

        switch (operator) {
            case "+":
                result = num1 + num2;
                break;
            case "-":
                result = num1 - num2;
                break;
            case "*":
                result = num1 * num2;
                break;
            case "/":
                if (num2 != 0) {
                    result = num1 / num2;
                } else {
                    System.out.println("Error: Division by zero is not allowed.");
                    return;
                }
                break;
            default:
                System.out.println("Error: Invalid operator.");
                return;
        }

        System.out.println("The result is: " + result);
    }
}

Step 4: Running the Program

Compile and run the program.
Enter two numbers and an operator when prompted.
The program will display the result of the operation.

Conclusion

In this tutorial, we learned how to create a simple calculator program in Java. We used the Scanner class to get user input and a switch statement to perform different operations based on the user's input. You can extend this program to include more features such as handling multiple operators and decimal numbers.

I hope this helps! Let me know if you have any questions.