Basic Calculator Program Using Java

Create a simple calculator which can perform basic arithmetic operations like addition, subtraction, multiplication, or division depending upon the user input.

Example:

Enter the numbers: 
2 
2

Enter the operator (+,-,*,/)
+
The final result:
2.0 + 2.0 = 4.0

Approach

• Take two numbers using the Scanner class. The switch case branching is used to execute a particular section.
• Using a switch case to evaluate respective operations.

Below is the Java program to implement the calculator:

Java

// Java program for simple calculator
import java.io.*;
import java.lang.*;
import java.lang.Math;
import java.util.Scanner;

// Driver class
public class BasicCalculator {
    // main function
    public static void main(String[] args)
    {
        // Stores two numbers
        double num1, num2;

        // Take input from the user
        Scanner sc = new Scanner(System.in);

        System.out.println("Enter the numbers:");

        // Take the inputs
        num1 = sc.nextDouble();
        num2 = sc.nextDouble();

        System.out.println("Enter the operator (+,-,*,/):");

        char op = sc.next().charAt(0);
        double o = 0;

        switch (op) {
        // case to add two numbers
        case '+':
            o = num1 + num2;
            break;

        // case to subtract two numbers
        case '-':
            o = num1 - num2;
            break;

        // case to multiply two numbers
        case '*':
            o = num1 * num2;
            break;

        // case to divide two numbers
        case '/':
            o = num1 / num2;
            break;

        default:
            System.out.println("You enter wrong input");
        }

        System.out.println("The final result:");
        System.out.println();

        // print the final result
        System.out.println(num1 + " " + op + " " + num2
                           + " = " + o);
    }
}

Output:

Enter the numbers:
2
2
Enter the operator (+,-,*,/)
+
The final result:
2.0 + 2.0 = 4.0

Time Complexity: O(1)

Auxiliary Space: O(1)