贪吃蛇小游戏-----C语言实现

1.分析

　　众所周知，贪吃蛇游戏是一款经典的益智游戏，有PC和手机等多平台版本，既简单又耐玩。该游戏通过控制蛇头方向吃食物，从而使得蛇变得越来越长，蛇不能撞墙，也不能装到自己，否则游戏结束。玩过贪吃蛇的朋友都知道这个小游戏有一圈“墙”、还有食物以及蛇，还有吃了食物之后的分数。所以通过C语言实现贪吃蛇，可以分为以下几个模块来实现：

　　a)编程实现“墙”

　　b)实现随机食物的生成

　　c)蛇的构建

　　d)以上三部分都实现了之后，实现游戏运行的部分，包括蛇的移动、吃食物、判断是否撞墙或者撞到自己。

　　e)游戏结束时的相关操作

2.具体思路

　　要通过C语言实现贪吃蛇，首先就要用C语言将贪吃蛇的相关信息描述出来。C语言提供了结构体类型，我们可以用结构体描述蛇的结点（结点的横纵坐标）、运动状态、总分数、每个食物的分数等等。

　　首先实现进入游戏的"welcome"界面，为了将“欢迎来到贪吃蛇游戏”打印到屏幕的中间，可以运用库函数先设置窗口的大小（system("mode con cols=100 lines=30");将窗口设置为长100，宽30），再通过库函数中的GetStdHandle函数、SetConsoleCursorPosition函数（把光标定位到我们需要的位置）将这句话打印到屏幕中央。

　　其次可以通过相同的方法将光标固定到我们需要的位置，用特殊字符‘■’打印实现墙（注意，‘■’在c中占用两个字符，所以在设置循环条件时要格外注意）

　　接着通过编程实现蛇的移动，本文中蛇是通过单链表实现的，因此在实现蛇的移动时，如果蛇接下来走的位置（上下左右）为食物，将这个位置的用指针表示，可以将食物头插到用_psnake指针维护的蛇身中，如果接下来的位置不是食物，同样头插到蛇身中，再将蛇的最后一个结点打印时输出为空格字符，然后free最后一个节点。

3.代码如下

snake.h:

#pragma once

#include<Windows.h>
#include<stdio.h>
#include<time.h>
#include<stdlib.h>

#define WALL "■"
#define FOOD "●"

#define INIT_X 20
#define INIT_Y 18
typedef struct SnakeNode
{
    int x;
    int y;
    struct SnakeNode *next;
}SnakeNode, *pSnakeNode;

//蛇的方向
enum Diretion
{
    UP,
    DOWN,
    LEFT,
    RIGHT
};

//状态
enum GameState
{
    OK,
    NORMAL_END,
    KILL_BY_WALL,
    KILL_BY_SELF
};
//游戏结构体
typedef struct Snake
{
    pSnakeNode _psnake;//维护蛇身的指针
    pSnakeNode _pFood;//维护食物的位置
    int _TotalScore;//总分数
    int _AddScore;//增加的分数
    int _SleepTime;//休眠时间
    enum Direction  _Dir;
    enum GameStatus _Status;
}Snake, *pSnake;

void GameStart(pSnake ps);
void WelcomeToGame();//欢迎界面函数
void SetPos(int x, int y);
void CreateMap();//创建地图
void InitSnake(pSnake ps);
void CreateFood(pSnake ps);//创建食物
void GameRun(pSnake ps);//运行游戏
void pause();//暂停函数

void snakmove(pSnake ps);
int NextHasFood(pSnakeNode pn, pSnakeNode pf);//判断下个结点是否为食物
void EatFood(pSnake ps,pSnakeNode pn);//吃食物
void NoFood(pSnake ps, pSnakeNode pn);//没有食物
void KillBYWALL(pSnake ps);
void KillBySelf(pSnake ps);
void GameEnd(pSnake ps);

snake.c:

#include"snake.h"
void  SetPos(int x, int y)
{
    COORD pos = { 0 };
    HANDLE handle = GetStdHandle(STD_OUTPUT_HANDLE);
    pos.X = x; pos.Y = y;
    SetConsoleCursorPosition(handle, pos);//把光标定位到我们需要的位置了
}
void WelcomeToGame()//欢迎界面函数
{
    //设置窗口大小
    system("mode con cols=100 lines=30");
    SetPos(40, 13);//分装的函数用来定位光标
    printf("欢迎来到贪吃蛇小游戏
");
    SetPos(35, 25);
    system("pause");//暂停
    system("cls");//清空屏幕
    SetPos(30, 9);
    printf("用↑，↓，←，→来控制蛇的移动，F1为加速，F2为减速
");
    SetPos(40, 11);
    printf("加速获得分数更多
");
    SetPos(35, 25);
    system("pause");
    system("cls");
}

void CreateMap()
{
    int i = 0;
    //上
    for (i = 0; i <= 58; i += 2)
    {
        SetPos(i, 0);
        printf(WALL);
    }
    //下
    for (i = 0; i <= 58; i += 2)
    {
        SetPos(i, 27);
        printf(WALL);
    }
    //左
    for (i = 1; i <= 26; i++)
    {
        SetPos(0, i);
        printf(WALL);
    }
    //右
    for (i = 1; i <= 26; i++)
    {
        SetPos(58, i);
        printf(WALL);
    }
}
pSnakeNode BuyNode()
{
    pSnakeNode pRet = (pSnakeNode)malloc(sizeof(SnakeNode));
    if (pRet == NULL)
    {
        perror("BuyNode::malloc()");
        exit(EXIT_FAILURE);
    }
    pRet->x = 0;
    pRet->y = 0;
    pRet->next = NULL;
    return pRet;
}
void InitSnake(pSnake ps)
{
    pSnakeNode first = BuyNode();//创建蛇头
    pSnakeNode cur = NULL;
    first->x = INIT_X;
    first->y = INIT_Y;
    int i = 0;
    for (i = 1; i <= 4; i++)
    {
        cur = BuyNode();//创建蛇身
        cur->x = first->x + 2;
        cur->y = first->y;
        cur->next = first;
        first = cur;
    }
    //打印蛇
    while (cur)
    {
        SetPos(cur->x, cur->y);
        printf(FOOD);
        cur = cur->next;
    }
    ps->_psnake = first;
}

void CreateFood(pSnake ps)
{
    pSnakeNode pfood = BuyNode();
    pSnakeNode cur = ps->_psnake;
    pfood->y = rand() % 26 + 1;
    do
    {
        pfood->x = rand() % 55 + 2;//0-54,+2产生2-56
    } while (pfood->x % 2 != 0);
    while (cur)
    {
        if (cur->x == pfood->x&&cur->y == pfood->y)
        {
            CreateFood(ps);
        }
        cur = cur->next;
    }
    ps->_pFood = pfood;
    SetPos(pfood->x, pfood->y);
    printf(FOOD);
}

void GameStart(pSnake ps)
{
    //打印欢迎界面
    WelcomeToGame();
    //创建地图，画墙
    CreateMap();
    //初始化蛇
    InitSnake(ps);
    //初始化食物
    CreateFood(ps);
    //游戏运行
    ps->_AddScore = 10;//每次增加的分数
    ps->_TotalScore = 0;//总分
    ps->_Dir = RIGHT;//方向
    ps->_SleepTime = 200;//0.2秒
    ps->_Status = OK;//状态
}

void pause()//暂停函数
{
    while (1)
    {
        Sleep(100);
        if (GetAsyncKeyState(VK_SPACE))
        {
            return;
        }
    }
}

int NextHasFood(pSnakeNode pn, pSnakeNode pf)
{
    return (pn->x == pf->x) && (pn->y == pf->y);
}

void EatFood(pSnake ps, pSnakeNode pn)//吃食物
{
    pSnakeNode cur = NULL;
    pn->next = ps->_psnake;//头插
    ps->_psnake = pn;
    cur = ps->_psnake;
    ps->_TotalScore += ps->_AddScore;
    while (cur)
    {
        SetPos(cur->x, cur->y);
        printf(FOOD);
        cur = cur->next;
    }
    CreateFood(ps);
}

void NoFood(pSnake ps, pSnakeNode pn)//没有食物
{
    pSnakeNode cur = NULL;
    pn->next = ps->_psnake;//头插
    ps->_psnake = pn;
    cur = ps->_psnake;
    while (cur->next->next)
    {
        SetPos(cur->x, cur->y);
        printf(FOOD);
        cur = cur->next;
    }
    SetPos(cur->x, cur->y);
    printf(FOOD);
    SetPos(cur->next->x, cur->next->y);
    printf(" ");
    free(cur->next);
    cur->next = NULL;
}

void snakmove(pSnake ps)//蛇的移动
{
    pSnakeNode pNextNode = BuyNode();
    SetPos(65, 8);
    printf("总分:%d", ps->_TotalScore);
    SetPos(65, 9);
    printf("每个食物的得分：%d ", ps->_AddScore);
    //上
    switch (ps->_Dir)
    {
        case UP:
        {
            pNextNode->x = ps->_psnake->x;
            pNextNode->y = ps->_psnake->y - 1;
            if (NextHasFood(pNextNode,ps->_pFood))
            {
                //下一个节点是食物
                EatFood(ps,pNextNode);
            }
            else
            {
                NoFood(ps,pNextNode);
            }
            break;
        }
        case DOWN:
        {
            pNextNode->x = ps->_psnake->x;
            pNextNode->y = ps->_psnake->y + 1;
            if (NextHasFood(pNextNode, ps->_pFood))
            {
              //下一个节点是食物
                  EatFood(ps, pNextNode);
              }
            else
            {
                  NoFood(ps, pNextNode);
            }
            break;
        }
        case LEFT:
        {
            pNextNode->x = ps->_psnake->x-2;
            pNextNode->y = ps->_psnake->y;
            if (NextHasFood(pNextNode, ps->_pFood))
            {
                //下一个节点是食物
                EatFood(ps, pNextNode);
            }
            else
            {
                NoFood(ps, pNextNode);
            }
            break;
        }
        case RIGHT:
        {
            pNextNode->x = ps->_psnake->x+2;
            pNextNode->y = ps->_psnake->y ;
            if (NextHasFood(pNextNode, ps->_pFood))
            {
                 //下一个节点是食物
                EatFood(ps, pNextNode);
            }
            else
            {
                NoFood(ps, pNextNode);
            }
            break;
        }
        default:
        {
            break;
        }
    }
}

void KillBYWALL(pSnake ps)
{
    if ((ps->_psnake->x == 0) ||
        (ps->_psnake->x == 58) || 
        (ps->_psnake->y == 0) ||
        (ps->_psnake->y == 27))
    {
        ps->_Status = KILL_BY_WALL;
    }
}

void KillBySelf(pSnake ps)
{
    pSnakeNode tnext = ps->_psnake->next;
    while (tnext)
    {
        if ((tnext->x == ps->_psnake->x) && (tnext->y == ps->_psnake->y))
        {
            ps->_Status = KILL_BY_SELF;
            return;
        }
        tnext = tnext->next;
    }

}
void PrintHelpInfo()
{
    SetPos(65, 11);
    printf("用↑，↓，←，→来控制蛇的移动");
    SetPos(65, 12);
    printf("F1为加速，F2为减速
");
    SetPos(65, 13);
    printf("加速获得分数更多
");
    SetPos(65, 14);
    printf("按空格暂停游戏
");

}

void GameEnd(pSnake ps)
{
    pSnakeNode cur = ps->_psnake;
    SetPos(25, 14);
    if (ps->_Status == NORMAL_END)
    {
        SetPos(70, 20);
        printf("游戏正常接结束
");
        SetPos(70, 21);
    }
    else if (ps->_Status == KILL_BY_SELF)
    {
        SetPos(70, 20);
        printf("蛇撞到自己了
");
        SetPos(70, 21);
    }
    else if (ps->_Status == KILL_BY_WALL)
    {
        SetPos(70, 20);
        printf("撞到墙了
");
        SetPos(70, 21);
    }
    while (cur)
    {
        pSnakeNode del = cur;
        cur = cur->next;
        free(del);
        del = NULL;
    }
    ps->_psnake = NULL;
    free(ps->_pFood);
    ps->_pFood = NULL;
}

void GameRun(pSnake ps)
{
    PrintHelpInfo();
    do
    {
        //确定方向
        if (GetAsyncKeyState(VK_UP)&&(ps->_Dir!=DOWN))
        {
            ps->_Dir = UP;
        }
        else if (GetAsyncKeyState(VK_DOWN) && ps->_Dir != UP)
        {
            ps->_Dir = DOWN;
        }
        else if (GetAsyncKeyState(VK_LEFT) && ps->_Dir != RIGHT)
        {
            ps->_Dir = LEFT;
        }
        else if (GetAsyncKeyState(VK_RIGHT) && ps->_Dir != LEFT)
        {
            ps->_Dir = RIGHT;
        }
        else if (GetAsyncKeyState(VK_SPACE))
        {
            //暂停游戏
            pause();
        }
        else if (GetAsyncKeyState(VK_ESCAPE))
        {
            //结束游戏
            ps->_Status = NORMAL_END;
            break;
        }
        else if (GetAsyncKeyState(VK_F1))
        {
            //加速
            if (ps->_SleepTime >= 40)
            {
                ps->_SleepTime -= 20;
                ps->_AddScore += 2;
            }
        }
        else if (GetAsyncKeyState(VK_F2))
        {
            //减速
            if (ps->_SleepTime <= 300)
            {
                ps->_SleepTime += 20;
                ps->_AddScore -= 2;
            }
            if (ps->_SleepTime > 300)
            {
                ps->_AddScore = 1;//不能一直减
            }
        }
        Sleep(ps->_SleepTime);//睡眠
        //蛇的移动
        snakmove(ps);
        KillBYWALL(ps);
        KillBySelf(ps);
    } while (ps->_Status == OK);
}

test.c:

#include"snake.h"

void test()
{
    srand((unsigned)time(NULL));
    Snake snake = { 0 };//创建贪吃蛇
    GameStart(&snake);
    GameRun(&snake);
    GameEnd(&snake);
}

int main()
{
    test();
    system("pause");
    return 0;
}