reversi

reversi.c

#include<stdio.h>

#define WIDTH 8
#define HEIGHT 8

#define EMPTY 0
#define BLACK 1
#define WHITE 2

#define TRUE 1
#define FALSE 0

int play_turn;
int field[HEIGHT][WIDTH];

//### initialize a game ###
void reversi_init() {
	int i,j;
	for(j = 0 ; j < HEIGHT ; ++j){
		for(i = 0 ; i < WIDTH ; ++i){
			field[j][i] = EMPTY;
		}
	}
	//initialize position
	field[HEIGHT / 2 - 1][WIDTH / 2 - 1] = BLACK;
	field[HEIGHT / 2    ][WIDTH / 2 - 1]  = WHITE;
	field[HEIGHT / 2 - 1][WIDTH / 2    ] = WHITE;
	field[HEIGHT / 2    ][WIDTH / 2    ] = BLACK;
	//other properties
	play_turn = 0;
}
// ### print a game status ###
void reversi_print(){
	int i,j;
	printf("<---------- turn %d ---------->\n",play_turn);
	/* header */
	printf("   |");
	for(i = 0 ; i < WIDTH ; ++i){
		printf("%2d |",i);
	}
	printf("\n");
	/* field */
	for(j = 0 ; j < HEIGHT ; ++j){
		printf("%2d |",j);
		for(i = 0 ; i < WIDTH ; ++i){
			switch(field[j][i]){
				case EMPTY:
					printf("   |");
					break;
				case BLACK:
					printf(" B |");
					break;
				case WHITE:
					printf(" W |");
					break;
				default:
					break;
			}
		}
		printf("\n");
	}
}
// ### check and reverse stone (recursive function) ###
// bw : BLACK or WHITE
// x : location x
// y : location y
// dx : reverse direction x
// dy : reverse direction y
// return value : can reverse it
int reversi_reverse(int bw,int x,int y,int dx,int dy){
	if(x < 0 || WIDTH <= x) return FALSE;
	if(y < 0 || HEIGHT <= y) return FALSE;
	if(field[y][x] == EMPTY) return FALSE;

	if(field[y][x] == bw) return TRUE;
	else {
		if(reversi_reverse(bw,x + dx,y + dy, dx, dy)){
			field[y][x] = bw;
			return TRUE;
		} else return FALSE;
	}
}

// ### check between same color stone and reverse
// bw : BLACK or WHITE
// x : put location x
// y : put location y
// return value : can reverse direction count
int reversi_check_others(int bw,int x,int y){
	int dir_count = 0;
	dir_count += reversi_reverse(bw,x, y - 1,  0, -1);//up
	dir_count += reversi_reverse(bw,x, y + 1,  0,  1);//down
	dir_count += reversi_reverse(bw,x - 1, y, -1,  0);//left
	dir_count += reversi_reverse(bw,x + 1, y,  1,  0);//right

	dir_count += reversi_reverse(bw,x - 1, y - 1, -1, -1);//up left
	dir_count += reversi_reverse(bw,x + 1, y - 1,  1, -1);//up right
	dir_count += reversi_reverse(bw,x - 1, y + 1, -1,  1);//down left
	dir_count += reversi_reverse(bw,x + 1, y + 1,  1,  1);//down right

	return dir_count;
}
// ### put a stone ###
//bw : put stone is black or white?
//x : put location x
//y : put location y
//return value : can put stone.
int reversi_put(int bw,int x,int y){
	/* area check */
	if(x < 0 || WIDTH <= x) return FALSE;
	if(y < 0 || HEIGHT <= y) return FALSE;
	/* already put */
	if(field[y][x] != EMPTY) return FALSE;
	if(reversi_check_others(bw,x,y) > 0){
		field[y][x] = bw;
		play_turn++;
		return TRUE;
	} else return FALSE;
}
int main(void) {
	int put_x,put_y,bw;
	/* initialize reversi */
	reversi_init();
	reversi_print();
	/* start player */
	bw = BLACK;//or WHITE
	while(1) {
		printf("%s's turn>",bw == WHITE ? "WHITE" : "BLACK");
		/* user input */
		scanf("%d %d",&put_x, &put_y);
		/* put */
		if(reversi_put(bw, put_x, put_y)){
			/* after put */
			bw = bw == WHITE ? BLACK : WHITE;//next turn change
			reversi_print();
		} else {
			/* miss */
			printf("cannot put a stone.\n");
		}
	}
	return 0;
}