C语言井字棋代码加注释

以下是 C 语言井字棋代码加注释：

#include <stdio.h>

#define BOARD_SIZE 3 // 定义棋盘大小为3

int board[BOARD_SIZE][BOARD_SIZE]; // 存储棋盘的二维数组

void init_board() { // 初始化棋盘，将所有位置都设置为0
    int i, j;
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            board[i][j] = 0;
        }
    }
}

void print_board() { // 打印棋盘
    int i, j;
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == 0) {
                printf("_ "); // 未下棋的位置用"_"表示
            } else if (board[i][j] == 1) {
                printf("X "); // 玩家1下的棋用"X"表示
            } else if (board[i][j] == 2) {
                printf("O "); // 玩家2下的棋用"O"表示
            }
        }
        printf("\n");
    }
}

int check_win(int player) { // 检查指定玩家是否胜利，player为1表示玩家1，player为2表示玩家2
    int i, j, win;

    // 检查每一行是否连成一线
    for (i = 0; i < BOARD_SIZE; i++) {
        win = 1;
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] != player) {
                win = 0;
                break;
            }
        }
        if (win) {
            return 1;
        }
    }

    // 检查每一列是否连成一线
    for (i = 0; i < BOARD_SIZE; i++) {
        win = 1;
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[j][i] != player) {
                win = 0;
                break;
            }
        }
        if (win) {
            return 1;
        }
    }

    // 检查对角线是否连成一线
    win = 1;
    for (i = 0; i < BOARD_SIZE; i++) {
        if (board[i][i] != player) {
            win = 0;
            break;
        }
    }
    if (win) {
        return 1;
    }

    // 检查反对角线是否连成一线
    win = 1;
    for (i = 0; i < BOARD_SIZE; i++) {
        if (board[i][BOARD_SIZE - 1 - i] != player) {
            win = 0;
            break;
        }
    }
    if (win) {
        return 1;
    }

    return 0; // 没有胜利返回0
}

int main() {
    int i, j, row, col, player = 1, num_moves = 0;

    init_board(); // 初始化棋盘

    while (1) {
        printf("Player %d's turn:\n", player);
        print_board(); // 打印棋盘

        printf("Enter row and column to place %c: ", player == 1 ? 'X' : 'O');
        scanf("%d %d", &row, &col);

        if (board[row][col] != 0) { // 如果该位置已有棋子，重新输入
            printf("Invalid move, try again.\n");
            continue;
        }

        board[row][col] = player; // 将棋子放入棋盘

        if (check_win(player)) { // 检查是否胜利
            printf("Player %d wins!\n", player);
            print_board();
            break;
        }

        num_moves++; // 记录下棋步数
        if (num_moves == BOARD_SIZE * BOARD_SIZE) { // 如果下满了棋盘，宣布平局
            printf("Draw!\n");
            print_board();
            break;
        }

        player = player == 1 ? 2 : 1; // 切换玩家
    }

    return 0;
}

注释中详细解释了每个函数和变量的作用，以及程序的流程。