* 3|4|5
* 6|7|8
*
- * Returns: 1 if a move is made succesfully. O if a move is invalid
- * (the given cell is not empty).
- *
- * Bugs: Currently this function always places X for all moves. So,
- * yeah, we'll need to fix that.
+ * Returns: TTT_ERROR_NONE if a move is made
+ * succesfully. TTT_ERROR_NOT_VALID_MOVE if a move is invalid (the
+ * given cell is not empty). TTT_ERROR_NOT_GRID if the move is
+ * impossible (user input 'a' or '9' etc.)
*/
-
ttt_error_t ttt_board_make_move (ttt_board_t *board, int move)
{
+ if (move < 0 || move > 8)
+ return TTT_ERROR_NOT_GRID;
+
if (board->cells[move] != TTT_CELL_EMPTY)
return TTT_ERROR_NOT_VALID_MOVE;
-
+
board->cells[move] = board->current_player;
-
+
if (board->current_player == TTT_CELL_X)
board->current_player = TTT_CELL_O;
else
board->current_player = TTT_CELL_X;
-
return TTT_ERROR_NONE;
}
+/* Checks to see if a player has won the game and should be called
+ * after every move.
+ *
+ * Returns: TTT_CELL_X if X's win. TTT_CELL_O if O's
+ * win. TTT_CELL_EMPTY if no win. The game can then check the value
+ * of the return and declare the winner.
+ */
+ttt_cell_t ttt_board_is_won (ttt_board_t *board)
+{
+ int i;
+ /* Loop over rows and columns looking for a win. */
+ for (i = 0; i < 3; i++)
+ {
+ /* Check the current column */
+ if (board->cells[i] != TTT_CELL_EMPTY &&
+ board->cells[i] == board->cells[i + 3] &&
+ board->cells[i] == board->cells[i + 6])
+ {
+ return board->cells[i];
+ }
+
+ /* Check the current row */
+ if (board->cells[i * 3] != TTT_CELL_EMPTY &&
+ board->cells[i * 3] == board->cells[(i * 3) + 1] &&
+ board->cells[i * 3] == board->cells[(i * 3) + 2])
+ {
+ return board->cells[i * 3];
+ }
+ }
+ if (board->cells[0] != TTT_CELL_EMPTY &&
+ board->cells[0] == board->cells[4] &&
+ board->cells[0]== board->cells[8])
+ {
+ return board->cells[0];
+ }
+ if (board->cells[2] != TTT_CELL_EMPTY &&
+ board->cells[2] == board->cells[4] &&
+ board->cells[2]== board->cells[6])
+ {
+ return board->cells[2];
+ }
+ return TTT_CELL_EMPTY;
+}