Validate PIN code programming exercise.

Pin code validation emergency!!! Coders needed!
ATM machines allow 4 or 6 digit PIN codes and PIN codes cannot contain anything but exactly 4 digits or exactly 6 digits.

Write a function that returns true if a given string is possible PIN code or false if not.

"1234" => true
"123456" => true
"12ab" => false

You can scroll down for the solution. Or not. It is a good solution so you should scroll down. Just saying. Came on, PLEASE 🙂 🙂

   public static bool ValidatePin(string pin)
  //again there is many ways do solve this coding problem
  //I just want to introduce the TryParse() function
  //So first we check if the length of the string is 4 or 6 
  //with the ||(OR) operator.
  //And then, about TryParse():
  //this function does not one but two things. 
  //It is not very usual for functions to do that.
  //The way it does it, is with this "out" keyword.
  //You can google it :)
  //1) converts string to a number 
  //2) returns true or false for the success of the operation 
  //The rest is simple
  //if the (the Length of the string) Length=4 or Length=6
  //and if the pin is successfully converted to a number
  //we return true. Else we return false.
        if (pin.Length==4 || pin.Length ==6)
            int r;
            if (int.TryParse(pin, out r)) return true;
            else  return false;                
            return false;