Minmax algorithm implemented in C.
To play you can make combinations chossing two of the three modes that are available to play, just exchange the arguments in the function's call ttt(board, argument_2, argument_3); in main() function by any combination of these players: minimax_strategy, random_strategy and human.
When running the game, the squares are referenced by the numbers 0 through 8 that are the squares of the board, if the input is mistyped or the square selected is already filled, nothing happens until you type a correct value.