using System;

​

namespace Calculator

{

    public class Program

    {

        public static void Main(string[] args)

        {

            while (true)

            {

                Console.Clear();

​

                int x = ReadInt("Please Enter a");

                Console.WriteLine("Do you want addition-a, subtraction-s, division-d, or multiplication-m, quit-q.");

                string input1 = Console.ReadLine().ToLower();

                if (input1 == "q") break;

                int y = ReadInt("Please Enter b");

                if (input1 == "a") Console.WriteLine(Add(x, y));

                else if (input1 == "s") Console.WriteLine(Subtract(x, y));

                else if(input1 == "d") Console.WriteLine(Divide(x, y));

                else if (input1 == "m") Console.WriteLine(Multiply(x, y));

                else Console.WriteLine("Invalid Input");

​

                Console.WriteLine("Press Enter");

                Console.ReadLine();

            }

​

        }

        static int ReadInt(string prompt)

        {

            Console.WriteLine(prompt);

            string inputStr = Console.ReadLine();

            int input = int.Parse(inputStr);

            return input;

        }

​

        static int Add(int a, int b)

        {

            return a + b;

        }

​

        static int Subtract(int a, int b)

        {

            return a + b;

        }

​

        static int Divide(int a, int b)

        {

            return a / b;

        }

​

        static int Multiply(int a, int b)

        {

            return a * b;

        }

    }

}

​