1 /* ttt.c - client-server tic-tac-toe game
3 * Copyright © 2005 Carl Worth
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2, or (at your option)
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software Foundation,
17 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * Author: Carl Worth <cworth@cworth.org>
23 #include "ttt-board.h"
24 #include "ttt-error.h"
26 /* Initialize an empty board. */
28 ttt_board_init (ttt_board_t *board)
31 for (i = 0; i < TTT_BOARD_MAX_CELLS; i++)
33 board->cells[i] = TTT_CELL_EMPTY;
35 board->current_player = TTT_CELL_X;
38 /* Initialize a board from its string representation.
40 * Returns: TTT_BOARD_SUCCESS or TTT_BOARD_INVALID_BOARD if the board
41 * string could not be properly parsed.
44 ttt_board_init_from_string (ttt_board_t *board,
49 for (i = 0; i < strlen (s); i++)
55 board->cells[j] = s[i];
62 /* Return the string representation of a board.
64 * The return value is a malloc()ed string that should be free()ed
65 * when no longer needed.
67 * Errors: If out-of-memory occurs, this function will not return.
70 ttt_board_to_string (ttt_board_t *board)
77 board->cells[0], board->cells[1], board->cells[2],
78 board->cells[3], board->cells[4], board->cells[5],
79 board->cells[6], board->cells[7], board->cells[8]);
83 /* Write a string representation of a board to the provided file.
85 * Errors: If out-of-memory or a file IO error occurs, this function
89 ttt_board_write (ttt_board_t *board, FILE *file)
93 s = ttt_board_to_string (board);
95 xfwrite (s, 1, strlen (s) + 1, file);
100 /* Makes a new move in the given board.
102 * The move value is a number from 0 to 9 giving the position to be
109 * Returns: TTT_ERROR_NONE if a move is made
110 * succesfully. TTT_ERROR_NOT_VALID_MOVE if a move is invalid (the
111 * given cell is not empty). TTT_ERROR_NOT_GRID if the move is
112 * impossible (user input 'a' or '9' etc.)
115 ttt_error_t ttt_board_make_move (ttt_board_t *board, int move)
117 if (move < 0 || move > 8)
118 return TTT_ERROR_NOT_GRID;
120 if (board->cells[move] != TTT_CELL_EMPTY)
121 return TTT_ERROR_NOT_VALID_MOVE;
123 board->cells[move] = board->current_player;
125 if (board->current_player == TTT_CELL_X)
126 board->current_player = TTT_CELL_O;
128 board->current_player = TTT_CELL_X;
129 return TTT_ERROR_NONE;
132 /* Checks to see if a player has won the game and should be called
135 * Returns: TTT_CELL_X if X's win. TTT_CELL_O if O's
136 * win. TTT_CELL_EMPTY if no win. The game can then check the value
137 * of the return and declare the winner.
140 ttt_cell_t ttt_board_is_won (ttt_board_t *board)
144 /* Loop over rows and columns looking for a win. */
145 for (i = 0; i < 3; i++)
147 /* Check the current column */
148 if (board->cells[i] != TTT_CELL_EMPTY &&
149 board->cells[i] == board->cells[i + 3] &&
150 board->cells[i] == board->cells[i + 6])
152 return board->cells[i];
155 /* Check the current row */
156 if (board->cells[i * 3] != TTT_CELL_EMPTY &&
157 board->cells[i * 3] == board->cells[(i * 3) + 1] &&
158 board->cells[i * 3] == board->cells[(i * 3) + 2])
160 return board->cells[i * 3];
164 if (board->cells[0] != TTT_CELL_EMPTY &&
165 board->cells[0] == board->cells[4] &&
166 board->cells[0]== board->cells[8])
168 return board->cells[0];
171 if (board->cells[2] != TTT_CELL_EMPTY &&
172 board->cells[2] == board->cells[4] &&
173 board->cells[2]== board->cells[6])
175 return board->cells[2];
178 return TTT_CELL_EMPTY;