gistfile1.txt

include <stdio.h>

// Prototype the functions
int CheckEndOfGame(int * squares);
int ChooseSquare(int * squares);
int MakeMoves(int * ctrMoves, int * playr, int * squares);

int main()
{	/* High Level - play one or more games:
Players make moves until one wins or it's a draw.
Announce the winner (or draw).
Ask player to play again; play game or stop.
*/

// Declare variables
int gameOver	= 0; // no, game is not over yet
int playGame	= 1; // yes, play the game

do // Play Game(s)
{	// Store all choices in an array of 9 squares (squares[9])
// initialize the array with spaces (space is ASCII 32)
int squares[9] = {32, 32, 32, 32, 32, 32, 32, 32, 32};
//	 ("X" is ASCII 88)
//	 ("O" is ASCII 79)
int ctrMoves	= 0; // no moves yet
int player	 = 0; // [[see "if" in MakeMoves]]

do // Make one move
{	gameOver = MakeMoves(&ctrMoves, &player, squares);
}
while (!gameOver);

// draw the board (before declaring a winner), then display
printf("\n");
printf(" %c | %c | %c \n", squares[6], squares[7], squares[8]);
printf("-----------\n");
printf(" %c | %c | %c \n", squares[3], squares[4], squares[5]);
printf("-----------\n");
printf(" %c | %c | %c \n", squares[0], squares[1], squares[2]);
printf("\n");

if (gameOver == 1)
printf("The game ended in a draw.\n");
else if (gameOver == 2)
printf("Congratulations! You won!\n");
else
printf("The computer won.\n");

printf("Play again? (1 is Yes, 0 is No). ");
scanf("%d", &playGame);

} while (playGame == 1);

/*
Wrapup
"Thanks"
clean up

Other
*/
return 0;
}

int MakeMoves(int * ctrMoves, int * playr, int * squares)
{	/* Middle Level - make one move, check for winner:
When X takes a turn, draw the board, ask for chosen square, store it.
When O takes a turn, program chooses square, store it if game not over.
*/

int endTheGame	= 0;	 // no, game has not ended yet
int thisSquare	= 0;
int drawTheBoard = 0;

// get a choice (from person or program), then store it in the array
if (*playr == 0)
{	printf("\n");
printf(" %c | %c | %c \n", squares[6], squares[7], squares[8]);
printf("-----------\n");
printf(" %c | %c | %c \n", squares[3], squares[4], squares[5]);
printf("-----------\n");
printf(" %c | %c | %c \n", squares[0], squares[1], squares[2]);
printf("\n");

*playr = 1;	 // it's now the person's turn

printf("Choose a square (1 - 9). \n");
scanf("%d", &thisSquare);

squares[thisSquare - 1] = 88;
// subtract 1 from thisSquare to get the array subscript
// eg, center square, 5, is square[4]
}
else
{	*playr = 0;	 // it's now the program's turn

thisSquare = ChooseSquare(squares);
if (thisSquare == 0)
*ctrMoves = 9;	 // tie - no squares left; game over
else
squares[thisSquare - 1] = 79;
// subtract 1 from thisSquare to get the array subscript
// eg, center square, 5, is square[4]
}

*ctrMoves = *ctrMoves + 1;
if (*ctrMoves > 9)
endTheGame = 1;	 // tie - no squares left; game over
else if (*ctrMoves >= 5) 
endTheGame = CheckForWinner(squares);

return endTheGame;
}

int ChooseSquare(int * squares)
{	/* Low Level (1) - find the best empty square
(eg, squares[4] == 32 means center square is open)
*/

if (squares[4] == 32)
return 5;
else
if (squares[0] == 32)
return 1;
else
if (squares[2] == 32)
return 3;
else
if (squares[6] == 32)
return 7;
else
if (squares[8] == 32)
return 9;
else
if (squares[1] == 32)
return 2;
else
if (squares[3] == 32)
return 4;
else
if (squares[5] == 32)
return 6;
else
if (squares[7] == 32)
return 8;
else
return 0;	 // tie - no squares left; game over
}

int CheckForWinner(int * squares)
{	/* Low Level (2) - check whether person won, program won, or draw
winners: 1-2-3 | 4-5-6 | 7-8-9 || 1-4-7 | 2-5-8 | 3-6-9 || 1-5-9 | 3-5-7
0 means game not over; 1 means draw; 2 means person won; 3 means program won
*/

if (squares[0] == squares[1] && squares[1] == squares[2] && squares[2] != 32)
{	// top row
if (squares[2] == 88)	// X won
return 2;
else
return 3;
}
else if (squares[3] == squares[4] && squares[4] == squares[5] && squares[5] != 32)
{	// middle row
if (squares[5] == 88)	// X won
return 2;
else
return 3;
}
else if (squares[6] == squares[7] && squares[7] == squares[8] && squares[8] != 32)
{	// bottom row
if (squares[8] == 88)	// X won
return 2;
else
return 3;
}

else if (squares[0] == squares[3] && squares[3] == squares[6] && squares[6] != 32)
{	// left column
if (squares[6] == 88)	// X won
return 2;
else
return 3;
}
else if (squares[1] == squares[4] && squares[4] == squares[7] && squares[7] != 32)
{	// middle column
if (squares[7] == 88)	// X won
return 2;
else
return 3;
}
else if (squares[2] == squares[5] && squares[5] == squares[8] && squares[8] != 32)
{	// right column
if (squares[8] == 88)	// X won
return 2;
else
return 3;
}

else if (squares[0] == squares[4] && squares[4] == squares[8] && squares[8] != 32)
{	// top left to bottom right
if (squares[8] == 88)	// X won
return 2;
else
return 3;
}
else if (squares[2] == squares[4] && squares[4] == squares[6] && squares[6] != 32)
{	// top right to bottom left
if (squares[6] == 88)	// X won
return 2;
else
return 3;
}
else
return	0;	// game not over
}