ماشین حساب ساده

using System;

class Program
{
    static void Main()
    {
        bool continueCalculating = true;
        
        while (continueCalculating)
        {
            Console.Clear();
            Console.WriteLine("=== Simple Calculator ===");
            Console.WriteLine("1. Addition (+)");
            Console.WriteLine("2. Subtraction (-)");
            Console.WriteLine("3. Multiplication (*)");
            Console.WriteLine("4. Division (/)");
            Console.WriteLine("5. Exit");
            Console.Write("Select operation: ");
            
            string choice = Console.ReadLine();
            
            if (choice == "5")
            {
                continueCalculating = false;
                Console.WriteLine("Exiting program...");
                continue;
            }
            
            Console.Write("Enter first number: ");
            double num1 = Convert.ToDouble(Console.ReadLine());
            
            Console.Write("Enter second number: ");
            double num2 = Convert.ToDouble(Console.ReadLine());
            
            double result = 0;
            bool validOperation = true;
            
            switch (choice)
            {
                case "1":
                case "+":
                    result = num1 + num2;
                    Console.WriteLine($"Result: {num1} + {num2} = {result}");
                    break;
                    
                case "2":
                case "-":
                    result = num1 - num2;
                    Console.WriteLine($"Result: {num1} - {num2} = {result}");
                    break;
                    
                case "3":
                case "*":
                    result = num1 * num2;
                    Console.WriteLine($"Result: {num1} × {num2} = {result}");
                    break;
                    
                case "4":
                case "/":
                    if (num2 != 0)
                    {
                        result = num1 / num2;
                        Console.WriteLine($"Result: {num1} ÷ {num2} = {result}");
                    }
                    else
                    {
                        Console.WriteLine("Error: Division by zero!");
                    }
                    break;
                    
                default:
                    Console.WriteLine("Invalid operation!");
                    validOperation = false;
                    break;
            }
            
            if (validOperation && choice != "5")
            {
                Console.WriteLine("\nPress Enter to continue...");
                Console.ReadLine();
            }
        }
    }
}