game.h
    #ifndef __GAME_H__
    #define __GAME_H__
    
    #define _CRT_SECURE_NO_WARNINGS
    #include <string.h>
    #include <stdlib.h>
    #include <time.h>
    #include <stdio.h>
    
    #define ROW 3
    #define COL 3
    
    void InitBoard(char board[ROW]
 
[COL], int row, int col);// 棋盤初始化
    void DisplayBoard(char board[ROW][COL], int row, int col);// 顯示棋盤
    void PlayerMove(char board[ROW][COL], int row, int col); //玩家下棋
    void ComputerMove(char board[ROW][COL], int row, int col); //電腦下棋
    char JudgeWin(char board[ROW][COL], int row, int col); //判斷是否遊戲結束
 

    
    
    #endif //__GAME_H__ 
    
    game.c
    #define _CRT_SECURE_NO_WARNINGS
    #include"game.h"
    
    void InitBoard(char board[ROW][COL] ,int row ,int col)
    {
    	memset(board, ' ', ROW*COL);
    }
    
    void DisplayBoard(char board[ROW][COL], int row, int col)
    {
    	int i =
 
 0;
    	int j = 0;
    
    	for (i = 0; i < ROW; i++)
    	{
    		for (j = 0; j < COL; j++)
    		{
    			if (j < COL - 1)
    				printf(" %c |", board[i][j]);
    			else
    				printf(" %c ", board[i][j]);
    		}
    		printf("\n");
    		for (j = 0; j < COL; j++)
    		{
    			if (i < ROW - 1)
    				printf("--- ");
    		}
    		printf("\n");
    
    	}
    }
    
    void PlayerMove(char board[ROW][COL], int row, int col)
    {
    	int x = 0;
    	int y = 0;
    	while (1)
    	{
    		printf("玩家走，請輸入座標:>");
    		scanf("%d%d", &x, &y);
    
    		if (x >= 0 && x <= ROW && y >= 0 && y <= COL)
    		{
    			if (' ' == board[x - 1][y - 1])
    			{
    				board[x - 1][y - 1] = 'X';
    				break;
    			}
    			else
    				printf("輸入錯誤，請重試\n");
    		}
    		else
    			printf("輸入錯誤，請重試\n");
    		
    	}
    
    }
    
    void ComputerMove(char board[ROW][COL] ,int row, int col)
    {
    	while (1)
    	{
    		int x = rand() % 3;
    		int y = rand() % 3;
    
    		if (' ' == board[x][y])
    		{
    			board[x][y] = '*';
    			break;
    		}
    	}
    	
    }
    
    static int JudgeFull(char board[ROW][COL],int row,int col)
    {
    	int i = 0;
    	int j = 0;
    	for (i = 0; i < row; i++)
    	{
    		for (j = 0; j < col; j++)
    		{
    			if (' ' == board[i][j])
    				return 0;
    		}
    	}
    	return 1;
    }
    
    char JudgeWin(char board[ROW][COL] ,int row ,int col)
    {
    	int i = 0;
    	int j = 0;
    
    	for (i = 0; i < row; i++)
    	{
    		if (board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] != ' ')
    			return board[i][0];
    	}
    
    	for (i = 0; i < row; i++)
    	{
    		if (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[i][0] != ' ')
    			return board[0][i];
    	}
    
    	if (board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] != ' ')
    		return board[1][1];
    	else if (board[0][2] == board[1][1] == board[2][0] && board[1][1] != ' ')
    		return board[1][1];
    	else if (JudgeFull(board, row ,col))
    		return 'R';
    }
    
    test.c
    #define _CRT_SECURE_NO_WARNINGS
    #include "game.h"
    
    void menu()
    {
    	printf("**************************\n");
    	printf("********  1.play  ********\n");
    	printf("********  0.quit  ********\n");
    	printf("**************************\n");
    }
    
    void game()
    {
    	char board[ROW][COL];
    	char key = '0';
    	InitBoard(board, ROW, COL);
    	DisplayBoard(board, ROW, COL);
    	while (1)
    	{
    		PlayerMove(board, ROW, COL);
    		ComputerMove(board, ROW, COL);
    		DisplayBoard(board, ROW, COL);
    		key = JudgeWin(board, ROW, COL);
    		printf("key = %c\n", key);
    
    		if (key == '*')
    		{
    			printf("電腦贏\n");
    			break;
    		}
    		if (key == 'X')
    		{
    			printf("玩家贏\n");
    			break;
    		}
    		if (key == 'R')
    		{
    			printf("平局\n");
    			break;
    		}
    
    	}
    
    }
    
    
    void test()
    {
    	int choose;
    	srand((unsigned int)time(NULL));
    	do
    	{
    		menu();
    		printf("請選擇:>");
    		scanf("%d", &choose);
    		switch (choose)
    		{
    			case 1: game(); break;
    			case 0: printf("即將退出遊戲\n"); break;
    			default: printf("輸入錯誤，請重試\n"); break;
    		}
    	} while (choose);
    
    }
    
    int main()
    {
    	test();
    	system("pause");
    	return 0;
    }