using System;

public class Program

{

    public static void Main()

    {

    start:

        int error = 0;

        double finalnum = 0;

        string op = " ";

        Console.WriteLine("First Number:");

        string firstnum = Console.ReadLine();

        double finalfirstnum = Convert.ToDouble(firstnum);

        operatorstart:

        Console.Clear();

        if(error==1) {Console.WriteLine("Error. Please Enter a Valid Operator!");

                      Console.WriteLine(" ");

                      goto errorcontinue;}

        errorcontinue:

        Console.WriteLine(finalfirstnum);

        Console.WriteLine("-------------------------------------");

        Console.WriteLine("Enter an Operator:");

        Console.WriteLine("Add [1], Subtract [2], Multiply [3], Divide [4]");

        int operator1 = Convert.ToInt32(Console.ReadLine());

        error = 0;

        int op2 = operator1;

        if(op2==1) {op = "+";}

        else if(op2==2) {op = "-";}

        else if(op2==3) {op = "*";}

        else if(op2==4) {op = "÷";}

        else {error = 1;

              goto operatorstart;

             }

        Console.Clear();

        Console.WriteLine(finalfirstnum);

        Console.WriteLine(op);

        Console.WriteLine("-------------------------------------");

        Console.WriteLine("Second Number:");

        string secondnum = Console.ReadLine();

        double finalsecondnum = Convert.ToDouble(secondnum);

        Console.Clear();

        switch(op2) {

            case 1:

                finalnum = finalfirstnum + finalsecondnum;

                break;

            case 2:

                finalnum = finalfirstnum - finalsecondnum;

                break;

            case 3:

                finalnum = finalfirstnum * finalsecondnum;

                break;

            case 4:

                finalnum = finalfirstnum / finalsecondnum;

                break;

            default:

                Console.Clear();

                Console.WriteLine("Restart and use a valid operator!");

                break;

        }

        Console.WriteLine(finalfirstnum);

        Console.WriteLine(op + " " + finalsecondnum);

        Console.WriteLine("-------------------------------------");

        Console.WriteLine(finalnum);

        Console.WriteLine(" ");

        Console.WriteLine(" ");

        Console.WriteLine("Type anything to clear");

        Console.ReadLine();

        Console.Clear();

        goto start;

        }

    }