title: user input validation of int length
body: <p>l am writing a class assignment for a simple login program where user will input username, password and mobile number on the console. My problem is on the mobile number, l want them to input a 10 digit number and only 10, if they input less or more than 10 it must show an error. Here is my code so far:</p>
  
  <pre><code>Console.WriteLine("Please enter your Mobile Number:");
  Console.WriteLine("**Please note Mobile Number should be 10 digits only e.g     07...");
  
  //AVOIDS EXCEPTION     HANDLING OF ENTERING ANY TYPE THAT IS NOT AN INTEGER
  while (!int.TryParse(Console.ReadLine(), out Option))    {
  
  Console.WriteLine("***************************************************");
                  Console.WriteLine("Please Enter a valid numerical value!");
                  Console.WriteLine("Please Enter option 1 or option 2:");
  }
  </code></pre>