Detailed steps and practical demonstration of implementing the Snake game in C++

#include<iostream>
#include<cmath>
#include<cstdlib>
#include<cstdio>
#include<ctime>
#include<conio.h>
#include<windows.h>
using namespace std;

/*光标定位*/
HANDLE hout = GetStdHandle(STD_OUTPUT_HANDLE);
COORD coord;
void  locate(int x, int y)
{
	coord.X = y;
	coord.Y = x;
	SetConsoleCursorPosition(hout,coord);
};

/*光标隐藏*/
void hide()
{
	CONSOLE_CURSOR_INFO cursor_info = {1,0}; //bVisible=0；隐藏光标
	SetConsoleCursorInfo(hout, &cursor_info);//获取光标状态
}

/*生成随机数*/
double random(double start, double end)
{
	return start + (end - start)*rand()/(RAND_MAX+1.0);//生成一个数，大于等于start，小于end；
}

/*定义地图的长和宽*/
int m, n;

/*定义蛇 的长度，坐标，方向，食物的位置*/
struct node
{
	int x, y;
}snake[1000];//蛇的坐标

int snake_length, dir;//蛇的长度，方向
node food;
int direct[4][2] = { {-1,0}, {1,0}, {0,-1}, {0,1} };//食物的位置

/*输出围墙：一个矩形框*/
void print_wall()
{
	//输出第一行 “----------”
	cout << " ";
	for (int i = 1; i <= n; i++)
	{
		cout << "-";
	}
	cout << endl;
	//输出第一列“|”，中间输入空格，最后一列输出“|”
	for (int j = 0; j <= m-1; j++)
	{
		cout << "|";
		for (int i = 1; i <= n; i++)
			cout << " ";
		cout << "|" << endl;
	}
	cout << " ";
	//输出最后一行“----------”
	for (int i = 1; i <= n; i++)
		cout << "-";
}

/*首次输出蛇，其中snake[0]代表头部*/
//蛇的外型：“@*****”
void print_snake()
{
	locate(snake[0].x,snake[0].y);
	cout << "@";
	for (int i = 1; i < snake_length - 1; i++)
	{
		locate(snake[i].x, snake[i].y);
		cout << "*";
	}
}

/*判断是否撞墙或者头部是否碰到身体的任意一个部位，碰到则游戏失败*/
bool is_correct()
{
	if (snake[0].x == 0 || snake[0].y == 0 || snake[0].x == m + 1 || snake[0].y == n + 1) return false;//头部碰到边缘
	for (int i = 1; i <= snake_length - 1; i++)
		if (snake[0].x == snake[i].x  &&  snake[0].y == snake[i].y)return false;//头部碰到身体的任意一个部位	
	return  true;
}

/*随机生成食物的位置*/
bool print_food()
{
	srand((unsigned)time(0));//随机种子
	bool e;
	while (1)
	{
		e = true;
		int i = (int)random(0,m)+1;
		int j = (int)random(0,n)+1;
		food.x = i; food.y = j;//食物的位置随机

		for (int k = 0; k <= snake_length - 1; k++) //食物不能出现在蛇的身体的任意位置处
		{
			if (snake[k].x == food.x  &&  snake[k].y == food.y)
			{
			   e= false;
			   break; 
			}
		}
		if (e)break;
	}

	//在食物的位置处标记,食物符号为“$”;
	locate(food.x,food.y);
	cout << "$";
	return true;
}

/*蛇的前进*/
bool go_ahead()
{
	node tmp;
	bool e = false;
	tmp = snake[snake_length-1];//蛇尾
	for (int i = snake_length - 1; i >= 1;i--)
	{
		snake[i] = snake[i - 1];//后移一位
	}
	snake[0].x += direct[dir][0];
	snake[0].y += direct[dir][1];
	locate(snake[1].x, snake[1].y);//定位到头部的后一位
	cout << "*";
	/*吃到食物*/
	if (snake[0].x == food.x&&snake[0].y == food.y)
	{
		snake_length++;
		e = true;
		snake[snake_length - 1] = tmp;
	}
	/*输出此时蛇状态*/
	if (!e)
	{
		locate(tmp.x, tmp.y);
		cout << " ";
	}
	else
		print_food();
	locate(snake[0].x, snake[0].y);
	cout << "@";
	/*** 如果自撞 ***/
	if (!is_correct())
	{
		system("cls");
		cout << "You lose!" << endl << "Length: " << snake_length << endl;
		return false;
	}
	return true;
	


}


int main()
{
	//游戏提示：
	cout << "--------------------贪吃蛇---------------------" << endl;
	cout << "请先输入两个数,表示地图大小.要求长宽均不小于10." << endl;
	cout << "请注意窗口大小,以免发生错位.建议将窗口调为最大." << endl;
	cout << "再选择难度.请在1-10中输入1个数,1最简单,10则最难" << endl;
	cout << "然后进入游戏画面,以方向键控制方向.祝你游戏愉快!" << endl;
	cout << "-----------------------------------------------" << endl;
	cin >> m >> n;
	if (m < 10 || n < 10 || m>25 || n>40)
	{
		cout << "ERROR" << endl;
		system("pause");
		return 0;
	}
	//输入难度系数：1-10;
	int hard;
	cin >> hard;
	if (hard <= 0 || hard > 100)
	{
		cout << "ERROR" << endl;
		system("pause");
		return 0;
	}
	//数据初始化：蛇的位置，长度，方向
	snake_length = 5;//长度
	clock_t a, b;
	char ch;
	double hard_len;
	for (int i = 0; i <= 4; i++)//位置
	{
		snake[i].x = 1;
		snake[i].y = 5 - i;
	}
	dir = 3;//方向
	//输出原始地图、食物和蛇
	system("cls");
	hide();
	print_wall();
	print_food();
	print_snake();
	//在（0，m+2）出显示长度：
	locate(m + 2, 0);
	cout << "Now Length:";
	//开始游戏
	while (1)
	{   /*难度随长度的增加而提高*/
		hard_len = (double)snake_length / (double)(m*n);
		/*调节时间，单位是ms*/
		a = clock();
		while (1)
		{
			b = clock();
			if (b - a >= (int)(400 - 30 * hard)*(1 - sqrt(hard_len)))break;
		}
		//接收键盘输入的方向
//https://blog.csdn.net/wenweimin/article/details/105561
		if (_kbhit())
		{
			ch = _getch();
			if (ch == -32)
			{
				ch = _getch();
				switch (ch)
				{
				case 72:if (dir == 2 || dir == 3)dir = 0; break;
				case 80:if (dir == 2 || dir == 3)dir = 1; break;
				case 75:if (dir == 0 || dir == 1)dir = 2; break;
				case 77:if (dir == 0 || dir == 1)dir = 3; break;
				}
			}
		}

		//前进
		if (!go_ahead())break;
		//输出此时的长度
		locate(m + 2, 12);
		cout << snake_length;
	}
	system("pause");
	return 0;

}