写一段C语言代码，不引用其他库，实现贪吃蛇游戏

以下是使用C语言编写的简单贪吃蛇游戏代码示例：

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <windows.h>

#define WIDTH 20
#define HEIGHT 20

int gameover;
int score;
int x, y;
int fruitX, fruitY;
int tailX[100], tailY[100];
int nTail;
enum Direction { STOP = 0, LEFT, RIGHT, UP, DOWN };
enum Direction dir;

void Setup()
{
    gameover = 0;
    dir = STOP;
    x = WIDTH / 2;
    y = HEIGHT / 2;
    fruitX = rand() % WIDTH;
    fruitY = rand() % HEIGHT;
    score = 0;
}

void Draw()
{
    system("cls"); // 清屏

    for (int i = 0; i < WIDTH + 2; i++)
        printf("#");
    printf("\n");

    for (int i = 0; i < HEIGHT; i++)
    {
        for (int j = 0; j < WIDTH; j++)
        {
            if (j == 0)
                printf("#");
            if (i == y && j == x)
                printf("O");
            else if (i == fruitY && j == fruitX)
                printf("*");
            else
            {
                int print = 0;
                for (int k = 0; k < nTail; k++)
                {
                    if (tailX[k] == j && tailY[k] == i)
                    {
                        printf("o");
                        print = 1;
                    }
                }
                if (!print)
                    printf(" ");
            }
            if (j == WIDTH - 1)
                printf("#");
        }
        printf("\n");
    }

    for (int i = 0; i < WIDTH + 2; i++)
        printf("#");
    printf("\n");

    printf("Score: %d\n", score);
}

void Input()
{
    if (_kbhit())
    {
        switch (_getch())
        {
        case 'a':
            dir = LEFT;
            break;
        case 'd':
            dir = RIGHT;
            break;
        case 'w':
            dir = UP;
            break;
        case 's':
            dir = DOWN;
            break;
        case 'x':
            gameover = 1;
            break;
        }
    }
}

void Logic()
{
    int prevX = tailX[0];
    int prevY = tailY[0];
    int prev2X, prev2Y;
    tailX[0] = x;
    tailY[0] = y;

    for (int i = 1; i < nTail; i++)
    {
        prev2X = tailX[i];
        prev2Y = tailY[i];
        tailX[i] = prevX;
        tailY[i] = prevY;
        prevX = prev2X;
        prevY = prev2Y;
    }

    switch (dir)
    {
    case LEFT:
        x--;
        break;
    case RIGHT:
        x++;
        break;
    case UP:
        y--;
        break;
    case DOWN:
        y++;
        break;
    }

    if (x < 0 || x >= WIDTH || y < 0 || y >= HEIGHT)
        gameover = 1;

    for (int i = 0; i < nTail; i++)
    {
        if (tailX[i] == x && tailY[i] == y)
            gameover = 1;
    }

    if (x == fruitX && y == fruitY)
    {
        score += 10;
        fruitX = rand() % WIDTH;
        fruitY = rand() % HEIGHT;
        nTail++;
    }
}

int main()
{
    Setup();

    while (!gameover)
    {
        Draw();
        Input();
        Logic();
        Sleep(10); // 控制游戏速度
    }

    printf("Game Over!\n");
    printf("Your Score: %d\n", score);

    return 0;
}

请注意，以上代码是一个简化的贪吃蛇游戏示例，仅供参考。具体实现方式可能根据个人需求进行修改和扩展。