public static void Main()
Console.WriteLine("First Number:");
string firstnum = Console.ReadLine();
double finalfirstnum = Convert.ToDouble(firstnum);
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());
Console.WriteLine(finalfirstnum);
Console.WriteLine("-------------------------------------");
Console.WriteLine("Second Number:");
string secondnum = Console.ReadLine();
double finalsecondnum = Convert.ToDouble(secondnum);
finalnum = finalfirstnum + finalsecondnum;
finalnum = finalfirstnum - finalsecondnum;
finalnum = finalfirstnum * finalsecondnum;
finalnum = finalfirstnum / finalsecondnum;
Console.WriteLine("Restart and use a valid operator!");
Console.WriteLine(finalfirstnum);
Console.WriteLine(op + " " + finalsecondnum);
Console.WriteLine("-------------------------------------");
Console.WriteLine(finalnum);