using System;

public class Program

{

    public static void Main()

        {

            Console.WriteLine(" Hello, welcome my extraordinarily Advanced Calculator!  ");

            Console.WriteLine(" Please press ENTER to continue.  ");

            Console.ReadLine();

            menu();

        }

​

        public static void menu()

        {

​

            int options; 

​

            Console.Clear();

​

            Console.WriteLine("        Menu");

            Console.WriteLine("______________________");

            Console.WriteLine(" ");

            Console.WriteLine("1. Add");

            Console.WriteLine("2. Subtract");

            Console.WriteLine("3. Multiply");

            Console.WriteLine("4. Divide");

            Console.WriteLine("5. Square Roots");

            Console.WriteLine("6. Exit ");

            Console.WriteLine("");

            Console.WriteLine("");

            Console.WriteLine("");

            Console.WriteLine("Please select a number from the menu:");

            options = int.Parse(Console.ReadLine());

​

            if ((options < 1)||(options >6))

                { menu();

                }

​

            if (options == 1)

            {

                add();

            }

            if (options == 2)

            {

                subtract();

            }

            if (options == 3)

            {

                multiply();

            }

            if (options == 4)

            {

                division();

            }

​

            if (options == 5)

            {

                SquareRoot();

            }

​

            if (options == 6)

            {

                exit();

            }

​

        }

​

        public static void add()

        {

​

            int number1;

            int number2;

            int answer;

​

​

            Console.Clear();

​

            Console.WriteLine("I am in Addition mode!");

            Console.WriteLine();

            Console.WriteLine("Please input the first number for me to add:");

            number1 = int.Parse(Console.ReadLine());

            Console.WriteLine();

            Console.WriteLine("Please input the second number for me to subtract:");

            number2 = int.Parse(Console.ReadLine());

​

            answer = number1 + number2;

​

            Console.WriteLine();

            Console.WriteLine(number1 + " + " + number2 + " = " + answer);

            Console.ReadLine();

            menu();

        }

           public static void subtract()

        {

​

            int number1;

            int number2;

            int answer;

​

​

            Console.Clear();

​

            Console.WriteLine("I am in Subtraction mode!");

            Console.WriteLine();

            Console.WriteLine("Please input the first number for me to subtract:");

            number1 = int.Parse(Console.ReadLine());

            Console.WriteLine();

            Console.WriteLine("Please input the second number for me to subtract:");

            number2 = int.Parse(Console.ReadLine());

​

            answer = number1 - number2;

​

            Console.WriteLine();

            Console.WriteLine(number1 + " - " + number2 + " = " + answer);

            Console.ReadLine();

            menu();

        }

               public static void multiply()

        {

​

            int number1;

            int number2;

            int answer;

​

​

            Console.Clear();

​

            Console.WriteLine("I am in Multiplication mode!");

            Console.WriteLine();

            Console.WriteLine("Please input the first number for me to multiply:");

            number1 = int.Parse(Console.ReadLine());

            Console.WriteLine();

            Console.WriteLine("Please input the second number for me to multiply:");

            number2 = int.Parse(Console.ReadLine());

​

            answer = number1 * number2;

​

            Console.WriteLine();

            Console.WriteLine(number1 + " * " + number2 + " = " + answer);

            Console.ReadLine();

            menu();

        }

               public static void division()

        {

​

            int number1;

            int number2;

            int answer;

​

​

            Console.Clear();

​

            Console.WriteLine("I am in Division mode!");

            Console.WriteLine();

            Console.WriteLine("Please input the first number for me to divide:");

            number1 = int.Parse(Console.ReadLine());

            Console.WriteLine();

            Console.WriteLine("Please input the second number for me to divide:");

            number2 = int.Parse(Console.ReadLine());

​

            answer = number1 / number2;

​

            Console.WriteLine();

            Console.WriteLine(number1 + " / " + number2 + " = " + answer);

            Console.ReadLine();

            menu();

        }

        public static void SquareRoot()

        {

            double number;

            double answer;  

​

            Console.Clear();

​

            Console.WriteLine("I am in Square Root mode!");

            Console.WriteLine();

            Console.WriteLine("Please enter a number and I will find its Square Root!");

            number = int.Parse(Console.ReadLine());

​

            answer = Math.Sqrt(number);

​

            Console.WriteLine("The Square Root of " + number + " is " + answer);

​

            Console.ReadLine();

            menu();

​

        }

    public static void exit()

        {

            Console.Clear();

​

            Console.WriteLine(" Thanks for using my extraordinarily advanced calculator!  ");

            Console.ReadLine();

​

            Environment.Exit(0);

        }

​

    }

​

​