编写一个C语言程序，让两个人在计算机上玩井字游戏

以下是一个简单的 C 语言代码实现：

#include <stdio.h>

// 定义井字游戏棋盘
char board[10] = {' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '};

// 函数声明
void print_board();
int is_winner(char);
int is_board_full();
void player_move(char, char);

// 主程序
int main() {
    printf("欢迎来到井字游戏！\n");
    print_board();
    char player1 = 'X';
    char player2 = 'O';
    while (1) {
        player_move(player1, '1');
        print_board();
        if (is_winner(player1)) {
            printf("玩家 %c 获胜！\n", player1);
            break;
        }
        if (is_board_full()) {
            printf("平局！\n");
            break;
        }
        player_move(player2, '2');
        print_board();
        if (is_winner(player2)) {
            printf("玩家 %c 获胜！\n", player2);
            break;
        }
        if (is_board_full()) {
            printf("平局！\n");
            break;
        }
    }
    return 0;
}

// 函数定义：打印棋盘
void print_board() {
    printf(" %c | %c | %c \n", board[1], board[2], board[3]);
    printf("---+---+---\n");
    printf(" %c | %c | %c \n", board[4], board[5], board[6]);
    printf("---+---+---\n");
    printf(" %c | %c | %c \n", board[7], board[8], board[9]);
}

// 函数定义：判断是否胜利
int is_winner(char player) {
    return (board[1] == player && board[2] == player && board[3] == player) ||
           (board[4] == player && board[5] == player && board[6] == player) ||
           (board[7] == player && board[8] == player && board[9] == player) ||
           (board[1] == player && board[4] == player && board[7] == player) ||
           (board[2] == player && board[5] == player && board[8] == player) ||
           (board[3] == player && board[6] == player && board[9] == player) ||
           (board[1] == player && board[5] == player && board[9] == player) ||
           (board[3] == player && board[5] == player && board[7] == player);
}

// 函数定义：判断棋盘是否已满
int is_board_full() {
    int i;
    for (i = 1; i <= 9; i++) {
        if (board[i] == ' ') {
            return 0;
        }
    }
    return 1;
}

// 函数定义：玩家下棋
void player_move(char player, char player_no) {
    int move;
    while (1) {
        printf("请玩家 %c (玩家%s) 下棋 (1-9): ", player, player_no);
        scanf("%d", &move);
        if (move >= 1 && move <= 9 && board[move] == ' ') {
            board[move] = player;
            break;
        } else {
            printf("无效的位置，请重新选择。\n");
        }
    }
}

玩家可以依次输入要下的位置，如下所示：

欢迎来到井字游戏！
   |   |
   |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
请玩家 X (玩家1) 下棋 (1-9): 1
 X |   |
   |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
请玩家 O (玩家2) 下棋 (1-9): 5
 X |   |
   |   |
   |   |
---+---+---
   |   |
 O |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
请玩家 X (玩家1) 下棋 (1-9): 2
 X | X |
   |   |
   |   |
---+---+---
   |   |
 O |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
请玩家 O (玩家2) 下棋 (1-9): 3
 X | X | O
   |   |
   |   |
---+---+---
   |   |
 O |   |
   |   |
---+---+---
   |   |
   |   |
   |   |
请玩家 X (玩家1) 下棋 (1-9): 9
 X | X | O
   |   |
   |   |
---+---+---
   |   |
 O |   |
   |   |
---+---+---
   |   |
   |   | X
   |   |
玩家 X 获胜！