请编写一段C语言代码，实现简单的五子棋游戏

下面是一个简单的五子棋游戏的C语言代码，使用了二维数组来表示棋盘和玩家输入的坐标来落子：

#include <stdio.h>

#define BOARD_SIZE 15

char board[BOARD_SIZE][BOARD_SIZE];

void init_board() {
    // 初始化棋盘
    for (int i = 0; i < BOARD_SIZE; i++) {
        for (int j = 0; j < BOARD_SIZE; j++) {
            board[i][j] = '+';
        }
    }
}

void print_board() {
    // 打印棋盘
    printf("   ");
    for (int i = 0; i < BOARD_SIZE; i++) {
        printf("%c ", 'A' + i);
    }
    printf("\n");
    for (int i = 0; i < BOARD_SIZE; i++) {
        printf("%2d ", i + 1);
        for (int j = 0; j < BOARD_SIZE; j++) {
            printf("%c ", board[i][j]);
        }
        printf("\n");
    }
}

int check_win(int x, int y) {
    // 判断胜负
    char c = board[x][y];
    int count = 1;
    // 横向
    for (int i = y + 1; i < BOARD_SIZE && board[x][i] == c; i++) {
        count++;
    }
    for (int i = y - 1; i >= 0 && board[x][i] == c; i--) {
        count++;
    }
    if (count >= 5) {
        return 1;
    }
    count = 1;
    // 纵向
    for (int i = x + 1; i < BOARD_SIZE && board[i][y] == c; i++) {
        count++;
    }
    for (int i = x - 1; i >= 0 && board[i][y] == c; i--) {
        count++;
    }
    if (count >= 5) {
        return 1;
    }
    count = 1;
    // 左上-右下
    for (int i = x + 1, j = y + 1; i < BOARD_SIZE && j < BOARD_SIZE && board[i][j] == c; i++, j++) {
        count++;
    }
    for (int i = x - 1, j = y - 1; i >= 0 && j >= 0 && board[i][j] == c; i--, j--) {
        count++;
    }
    if (count >= 5) {
        return 1;
    }
    count = 1;
    // 右上-左下
    for (int i = x - 1, j = y + 1; i >= 0 && j < BOARD_SIZE && board[i][j] == c; i--, j++) {
        count++;
    }
    for (int i = x + 1, j = y - 1; i < BOARD_SIZE && j >= 0 && board[i][j] == c; i++, j--) {
        count++;
    }
    if (count >= 5) {
        return 1;
    }
    return 0;
}

int main() {
    int x, y;
    char player = 'X';
    init_board();
    while (1) {
        print_board();
        printf("Player %c's turn\n", player);
        printf("Enter the coordinates (e.g. A1): ");
        scanf("%c%d", &y, &x);
        x--;
        y -= 'A';
        getchar(); // 读取换行符
        if (board[x][y] == '+') {
            board[x][y] = player;
            if (check_win(x, y)) {
                printf("Player %c wins!\n", player);
                break;
            }
            player = player == 'X' ? 'O' : 'X';
        } else {
            printf("Invalid move! Please try again.\n");
        }
    }
    return 0;
}