程序代码：

#include <stdlib.h>
#include <malloc.h>
#include <stdio.h>
#include "game.h"
#include "snail.h"

int isStart = 0;

typedef struct tagPoint{
    int x;
    int y;
    struct tagPoint *next;
}Lnode,*LinkList;


Lnode snail;
int dx, dy;

Lnode food;
int score;

Lnode * creatlinklist()  //创建一个带头结点的空链表。本函数返回一个Lnode型指针变量
{    
    int temp;
    Lnode *L;   //Lnode型指针变量L
    L=(Lnode *)malloc(sizeof(Lnode));    //创建头结点
    L->next=NULL;
    return L;         //返回头结点的值以便于对该链表进行其他的操作
}


void drawsnail(Lnode *L)//画出当前链表中存储的蛇的信息
{
    Lnode *p;
    p=L;
    while (p!=NULL)
    {
        DrawRect(p->x,p->y,0,255,255);//Drawrect函数用来在屏幕上用矩形显示蛇。后面是RGB分量
        p=p->next;
    }
    
}

Lnode * step1(Lnode *L)//吃到食物表头加一，表尾不变
{
    Lnode *p,*n;
    p=L;
    n=(Lnode *)malloc(sizeof(Lnode));
    n->x=food.x;
    n->y=food.y;
    n->next=p;
    drawsnail(n);
    return n;
}
Lnode * step2(Lnode *L)//没有吃到食物，表头加一同时表尾删除一个节点
{
    Lnode *p,*n;
    p=L;
    n=(Lnode *)malloc(sizeof(Lnode));
    n->x=snail.x;
    n->y=snail.y;
    n->next=p;//表头加一
    while (p->next!=NULL)
    {
        p=p->next;
    }
    p=NULL;
    drawsnail(n);
    return n;
}





void GameStart(){
    isStart = 1;
    dx = 1; dy = 0;
    food.x = rand() % GRID_X;
    food.y = rand() % GRID_Y;
}



void GameUpdate(){
    Lnode *L;
    
    L=creatlinklist();


    if (isStart){

        // 游戏在运行中
        snail.x = (snail.x + dx + GRID_X) % GRID_X;
        snail.y = (snail.y + dy + GRID_Y) % GRID_Y;

        if (snail.x == food.x && snail.y == food.y)
        {
            // 吃到了
            L=step1(L);
            
            score += 10;    //加分
            UpdateScore(score);
            // 重新产生food位置
            food.x = rand() % GRID_X;
            food.y = rand() % GRID_Y;

        }
        else
        {//没有吃到
            L=step2(L);


        }


        if (score == 100){
            // 结束游戏
            isStart = 0;    //这个必须先，否则。。。。哈哈
            EndShowScore(score);
        }

    }else{
        // 游戏处于暂停中，或者未开始
        snail.x = 10;
        snail.y = 10;

        score = 0;
        UpdateScore(score);

    }



    // 绘图
//    DrawRect(snail.x,snail.y,0,255,255);
    DrawRect(food.x,food.y,255,0,0);
}

void GameKeyPress(int key){
    switch(key){
        case KEY_UP: dx = 0; dy = -1; break;
        case KEY_DOWN: dx = 0; dy = 1; break;
        case KEY_LEFT: dx = -1; dy = 0; break;
        case KEY_RIGHT: dx = 1; dy = 0; break;
    }
}

void GameOver(){

}