using System;

public class Program

{

        static void Main(string[] args)

        {

            bool The_First_Time = true;

            if (The_First_Time == true)

            {

                Console.Write("Welcome To Calculator Code \n \n");

            }

            string value;

            do

            {

                double res;

                Console.Write("Enter First Number: ");

                double num1 = Convert.ToDouble(Console.ReadLine());

                Console.Write("Enter Second Number: ");

                double num2 = Convert.ToDouble(Console.ReadLine());

                Console.Write("1.Addition\n2.Subtraction\n3.Multiplication\n4.division\nChoose The Operation You Need : ");

                int Operation = Convert.ToInt32(Console.ReadLine());

                switch (Operation)

                {

                    case 1:

                        res = num1 + num2;

                        Console.WriteLine("Result = {0}", res);

                        break;

                    case 2:

                        res = num1 - num2;

                        Console.WriteLine("Result = {0}", res);

                        break;

                    case 3:

                        res = num1 * num2;

                        Console.WriteLine("Result = {0}", res);

                        break;

                    case 4:

                        res = num1 / num2;

                        Console.WriteLine("Result = {0}", res);

                        break;

                    default:

                        Console.WriteLine("Wrong input");

                        break;

                }

                Console.Write("Do you want to continue(Y/N): ");

                value = Console.ReadLine();

                The_First_Time = false;

            }

            while (value == "y" || value == "Y");

            if (value == "N" || value == "n")

            {

                Console.WriteLine("Thanks For Using The Calculator Code");

            }

        }

}

​