贪吃蛇(C++)

一、项目思路

该项目用于计算机软件课设。贪吃蛇要解决的问题有：蛇身的移动，事物的随机生成，蛇头与食物重合，蛇吃食物身体的变长。蛇身移动的处理可以改变蛇首元素（蛇身用数组存储）的坐标，剩下的依次前移即可。蛇身的变长只需尾部添上一个数组元素即可。

二、源代码

#include<graphics.h>
#include<Windows.h>
#include<conio.h>
#include<ctime>
#include<vector>
#include<cstdlib>
using namespace std;
class Snake
{
public:
    Snake();
    bool check();//检测生成的食物是否和蛇重合了
    void SnakeMove();
    void startup();
    void clean();
    void show();
    void UpdateWithoutInput();
    void UpdateWithInput();
    void gameover();
private:
    int High;
    int Width;
    int Background;
    int dir;//方向
    int score;
    int speed;//画面更新速度，动态难度
    int food_x, food_y;
    vector<int> snake_x, snake_y; //蛇的每一节的坐标
};
Snake::Snake()
{
    High = 720;
    Width = 1280;
    Background = LIGHTGRAY;//easyx的颜色宏
    dir = 5;//方向参考1235键位，类似wasd
    score = 0;
    speed = 300;
    food_x = rand() % (Width - 40) + 21; //限定食物出现在屏幕范围内
    food_y = rand() % (High - 40) + 21;
    snake_x.resize(4), snake_y.resize(4);//蛇的初始长度为4
}
bool Snake::check()
{
    for (int i = 0; i < snake_x.size(); i++)
    {
        if ((food_x >= snake_x[i] - 40 && food_x <= snake_x[i] + 40) &&
            (food_y >= snake_y[i] - 40 && food_y <= snake_y[i] + 40))
            return false;
    }
    return true;
}
void Snake::SnakeMove()
{
    srand((unsigned int)(time)(NULL));
    //如果蛇头的坐标和食物的坐标有一定程度的重合，那么在蛇尾增加新的坐标
    if (food_x >= snake_x[0] - 20 &&
        food_x <= snake_x[0] + 20 &&
        food_y >= snake_y[0] - 20 &&
        food_y <= snake_y[0] + 20)
    {
        if (dir == 1)
        {
            snake_x.push_back(snake_x[snake_x.size() - 1] + 40);
            snake_y.push_back(snake_y[snake_y.size() - 1]);
        }
        else if (dir == 2)
        {
            snake_x.push_back(snake_x[snake_x.size() - 1]);
            snake_y.push_back(snake_y[snake_y.size() - 1] - 40);
        }
        else if (dir == 3)
        {
            snake_x.push_back(snake_x[snake_x.size() - 1] - 40);
            snake_y.push_back(snake_y[snake_y.size() - 1]);
        }
        else if (dir == 5)
        {
            snake_x.push_back(snake_x[snake_x.size() - 1]);
            snake_y.push_back(snake_y[snake_y.size() - 1] + 40);
        }

        score++;//加分
        if (speed >= 150) //调整速度
        {
            speed -= 5 * score;
        }
        //擦除旧食物，更新食物的坐标
        setlinecolor(Background);
        setfillcolor(Background);
        fillcircle(food_x, food_y, 20);
        food_x = rand() % (Width - 40) + 21;
        food_y = rand() % (High - 40) + 21;
        //如果生成的食物坐标和蛇重合了，再更新食物的坐标,check是检测是否重合的函数。
        while (!check())
        {
            food_x = rand() % (Width - 40) + 21;
            food_y = rand() % (High - 40) + 21;
        }
    }
    //蛇移动，通过从后往前迭代更新坐标，形成移动
    for (int i = snake_x.size() - 1; i > 0; i--)
    {
        snake_x[i] = snake_x[i - 1];
        snake_y[i] = snake_y[i - 1];
    }
    //头节点根据方向特殊处理
    if (dir == 1)
    {
        snake_x[0] = snake_x[1] - 40;
        snake_y[0] = snake_y[1];
    }
    else if (dir == 2)
    {
        snake_x[0] = snake_x[1];
        snake_y[0] = snake_y[1] + 40;
    }
    else if (dir == 3)
    {
        snake_x[0] = snake_x[1] + 40;
        snake_y[0] = snake_y[1];
    }
    else if (dir == 5)
    {
        snake_x[0] = snake_x[1];
        snake_y[0] = snake_y[1] - 40;
    }
    //检测是否撞墙或者咬到自己了
    for (unsigned i = 1; i < snake_x.size(); i++)
    {
        if ((snake_x[0] >= snake_x[i] - 20 &&
            snake_x[0] <= snake_x[i] + 20 &&
            snake_y[0] >= snake_y[i] - 20 &&
            snake_y[0] <= snake_y[i] + 20) ||
            ((snake_x[0] - 20 <= 0) ||
                (snake_x[0] + 20 >= 1280) ||
                (snake_y[0] - 20 <= 0) ||
                (snake_y[0] + 20 >= 720)))
        {//停留三秒退出游戏
            Sleep(3000);
            exit(0);
        }
    }
}
void Snake::startup()
{
    srand((unsigned int)(time)(NULL));
    initgraph(Width, High);
    setbkcolor(Background);
    cleardevice();
    for (int i = 0; i < 4; i++)
    {
        snake_x[i] = Width / 2 - 40 * i;
        snake_y[i] = High / 2;
    }
    BeginBatchDraw();
}
void Snake::clean()
{
    setlinecolor(Background);//设置线的颜色
    setfillcolor(Background);//设置填充色
    for (unsigned i = 0; i < snake_x.size(); i++)
    {
        fillcircle(snake_x[i], snake_y[i], 20);//画圆
    }
}
void Snake::show()
{
    for (unsigned i = 0; i < snake_x.size(); i++)
    {
        if (i == 0)
        {
            setfillcolor(LIGHTMAGENTA);
            fillcircle(snake_x[i], snake_y[i], 20);
        }
        else
        {
            setfillcolor(LIGHTRED);
            fillcircle(snake_x[i], snake_y[i], 20);
        }
    }

    FlushBatchDraw();//与BeginBatchDraw配合使用
    setfillcolor(YELLOW);
    //以下均为字体设置与字体显示，用于显示分数
    TCHAR s[5];
    fillcircle(food_x, food_y, 20);
    settextstyle(60, 0, _T("宋体"));
    settextcolor(RGB(25, 32, 94));
    _stprintf_s(s, 5, _T("%d"), score);
    outtextxy(430, 620, _T("Score:"));
    outtextxy(640, 620, s);

    Sleep(speed);//用sleep控制速度，speed越小蛇动的越快
}
void Snake::UpdateWithoutInput()
{
    SnakeMove();
}
void Snake::UpdateWithInput()
{
    char input;
    if (_kbhit())
    {
        input = _getch();
        if ((input == 'a' || input == '1') && dir != 3)
        {
            dir = 1;
            SnakeMove();
        }
        else if ((input == 's' || input == '2') && dir != 5)
        {
            dir = 2;
            SnakeMove();
        }
        else if ((input == 'w' || input == '5') && dir != 2)
        {
            dir = 5;
            SnakeMove();
        }
        else if ((input == 'd' || input == '3') && dir != 1)
        {
            dir = 3;
            SnakeMove();
        }
        if (input == 27)
        {
            input = 'n';
            while (1)
            {
                input = _getch();
                if (input == 27)
                    break;
            }
        }
    }
}
void Snake::gameover()
{
    EndBatchDraw();
    closegraph();
}

int main()
{
    Snake my_snake;
    my_snake.startup();
    while (1)
    {
        my_snake.clean();
        my_snake.UpdateWithoutInput();
        my_snake.UpdateWithInput();
        my_snake.show();
    }
    my_snake.gameover();
    return 0;
}

三、项目总结

该项目较为简单，无复杂算法。