Text-Based Calculator Made in C#.

using System;

namespace Simple_Calculator
{
    class Calc
    {

        public static String num1String;
        public static String num2String;
        public static double num1;
        public static double num2;
        public static String oper;
        public static String response;

        public static void Main (string[] args)
        {

            Console.Title = "Simple Calculator";

            Console.WriteLine ("Simple Text-Based Calculator by Aaron Murphy");
            Console.Write ("First Number>> ");
            num1String = Console.ReadLine ();

            try {

                num1 = Convert.ToInt32 (num1String);

            } catch(Exception) {

                Console.WriteLine ("You did not enter a number. Restarting...");
                Console.WriteLine ("");
                Main (null);

            }
            Console.WriteLine ("");

            Console.Write ("Second Number>> ");
            num2String = Console.ReadLine ();

            try {

                num2 = Convert.ToInt32 (num2String);
                Console.WriteLine ("");

            } catch(Exception) {

                Console.WriteLine ("You did not enter a number. Restarting...");
                Console.WriteLine ("");
                Main (null);

            }

            Console.Write ("Operator(+, -, *, /, sin, cos, %, log, exp, and tan)>> ");
            oper = Console.ReadLine ();
            Console.WriteLine ("");

            if (oper == "+") {

                Console.WriteLine (num1 + " + " + num2 + " = " + (num1 + num2));

            } else if (oper == "-") {

                Console.WriteLine (num1 + " - " + num2 + " = " + (num1 - num2));

            } else if (oper == "*") {

                Console.WriteLine (num1 + " * " + num2 + " = " + (num1 * num2));

            } else if (oper == "/") {

                Console.WriteLine (num1 + " / " + num2 + " = " + (num1 / num2));

            } else if (oper == "sin") {

                Console.WriteLine ("Sin(" + num1 + ") = " + Math.Sin (num1));

            } else if (oper == "cos") {

                Console.WriteLine ("Cos(" + num1 + ") = " + Math.Cos(num1));

            } else if (oper == "%") {

                Console.WriteLine (num1 + " % " + num2 + " = " + (num1 % num2));

            } else if (oper == "log") {

                Console.WriteLine ("Log(" + num1 + ") = " + Math.Log(num1));

            } else if (oper == "exp") {

                Console.WriteLine (num1 + "˄" + num1 + " = " + (Math.Pow(num1, num2)));

            } else if (oper == "tan") {

                Console.WriteLine ("Log(" + num1 + ") = " + Math.Tan(num1));

            }

            Console.WriteLine ("");
            Console.Write ("Do you want to perform a new calculation(Y/N)?>> ");
            response = Console.ReadLine ();

            if (response == "Y" || response == "y") { //It works if the user types "Y" or "y".

                Console.WriteLine ("");
                Main (null);

            }

        }
    }
}