title: Writing a Code for 3D tic tac toe. Don't know how to sum lines with given lines array
body: <p>I'm trying to do a 3D tic-tac-toe game, and I've gotten user input down, but I'm working on the computer playing. I want to sum the lines and transverse this array to see if any of the lines equal 15. (X = 5) in the code. So anytime the user has 3 X's in a row it adds to 15 and I want the computer to block the 4th X. How would I sum my lines and traverse this 76 line array that includes all possible lines winning combinations could be on?
  <a href="http://i.stack.imgur.com/Baw02.png" rel="nofollow">First part of my code including part of the 76 line array</a></p>
  
  <p>Also, how would I make it so if a number is entered twice it prompts the computer/player to use a different number?</p>