JavaConsoleCalculator.java

package JavaConsoleCalculator;

import java.util.Scanner;

public class JavaConsoleCalculator {

    
    public static double add(double a, double b) { 
        return a + b; 
    } 

    public static double subtract(double a, double b) { 
        return a - b; 
    }

    public static double multiply(double a, double b) { 
        return a * b; 
    }

    public static Double divide(double a, double b) {
        if (b == 0) {
            System.out.println("Error: Cannot divide by zero!");
            return null;
        }
        return a / b;
    }

    public static void printResult(double result) {
        if (result == (int) result) {
            System.out.println("Result: " + (int) result);
        } else {
            System.out.println("Result: " + result);
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        boolean exit = true;

        System.out.println("<--- Welcome to Java Console Calculator --->");

        while (exit) {
            System.out.println("Select an operation you want to perform:");
            System.out.println("1. Addition");
            System.out.println("2. Subtraction");
            System.out.println("3. Multiplication");
            System.out.println("4. Division");
            System.out.println("5. Exit");

            System.out.print("Enter Your Choice----: ");

            if (sc.hasNextInt()) {
                int choice = sc.nextInt();

                double num1, num2;
                Double result = null;

                switch (choice) {
                    case 1: 
                        System.out.print("Enter first number: ");
                        num1 = sc.nextDouble();

                        System.out.print("Enter second number: ");
                        num2 = sc.nextDouble();
                        result = add(num1, num2);
                        break;

                    case 2: 
                        System.out.print("Enter first number: ");
                        num1 = sc.nextDouble();

                        System.out.print("Enter second number: ");
                        num2 = sc.nextDouble();
                        result = subtract(num1, num2);
                        break;

                    case 3: 
                        System.out.print("Enter first number: ");
                        num1 = sc.nextDouble();

                        System.out.print("Enter second number: ");
                        num2 = sc.nextDouble();
                        result = multiply(num1, num2);
                        break;

                    case 4: 
                        System.out.print("Enter first number: ");
                        num1 = sc.nextDouble();

                        System.out.print("Enter second number: ");
                        num2 = sc.nextDouble();
                        result = divide(num1, num2);
                        break;

                    case 5: 
                        exit = false;
                        System.out.println("<--- Exiting the Calculator --->");
                        break;

                    default:
                    System.out.println("Invalid choice, Please select a valid choice!");
                    break;
                    
                }
                if (result != null) {
                    printResult(result);
                }
                System.out.println("-----------------------------------------");

            } else {
                System.out.println("Invalid choice, Please select a valid choice!");
                sc.next();
                continue;
            }
        }
        sc.close();
        
    }
}