2005-12-14 Carl Worth <cworth@cworth.org>

[ttt] / src / ttt-board.c

diff --git a/src/ttt-board.c b/src/ttt-board.c
index 9e9db9889394a5b719aa1cba68a8b92abf66ec30..f8f62e045de587631fa10c5c1caceee3a3fdecd0 100644 (file)
--- a/src/ttt-board.c
+++ b/src/ttt-board.c
@@ -19,13 +19,20 @@
  * Author: Carl Worth <cworth@cworth.org>
  */
 
+#include <stdio.h>
 #include "ttt-board.h"
+#include "ttt-error.h"
 
 /* Initialize an empty board. */
 void
 ttt_board_init (ttt_board_t *board)
 {
-    /* XXX: NYI */
+    int i;
+    for (i = 0; i < TTT_BOARD_MAX_CELLS; i++)
+    {
+       board->cells[i] = TTT_CELL_EMPTY;
+    }
+    board->current_player = TTT_CELL_X;
 }
 
 /* Initialize a board from its string representation.
@@ -50,7 +57,15 @@ ttt_board_init_from_string (ttt_board_t *board,
 char *
 ttt_board_to_string (ttt_board_t *board)
 {
-    /* XXX: NYI */
+    char *s;
+    xasprintf (&s, "\r\n" 
+              "%c|%c|%c\r\n"
+              "%c|%c|%c\r\n"
+              "%c|%c|%c",
+              board->cells[0], board->cells[1], board->cells[2], 
+              board->cells[3], board->cells[4], board->cells[5], 
+              board->cells[6], board->cells[7], board->cells[8]); 
+    return s;
 }
 
 /* Write a string representation of a board to the provided file.
@@ -70,3 +85,76 @@ ttt_board_write (ttt_board_t *board, FILE *file)
     free (s);
 }
 
+/* Makes a new move in the given board.
+ *
+ * The move value is a number from 0 to 9 giving the position to be
+ * moved as follows:
+ * 
+ *  0|1|2
+ *  3|4|5
+ *  6|7|8
+ *
+ * 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_t ttt_board_make_move (ttt_board_t *board, int move)
+{  
+    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.
+ * 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 <= 2; 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;
+}