#include <bios.h>
#include <conio.h>
#include <dos.h>
#include <graphics.h>
#include <stdlib.h>
#include <time.h>
using namespace std;

inline void display(char gsDomain[][22], int level, int moveSpeed)
{
system("cls"); //清屏
cout << endl << endl;
for (int i = 0; i < 22; i++)
{
cout << "\t";
for (int j = 0; j < 22; j++)
cout << gsDomain[i][j] << " ";
if (i == 0)
{
cout << "\tLevel：" << level;
}
else if (i == 3)
{
cout << "\t自動前進時間";
}
else if (i == 5)
{
cout << "\t間隔：" << moveSpeed << " ms";
}

cout << endl;
}
}

int main()
{
char gsDomain[22][22]; //貪吃蛇活動區(qū)域(包括墻壁)
//初始化貪吃蛇活動區(qū)域(不包括墻壁)
for (int i = 1; i <= 21; i++)
{
for (int j = 1; j <= 21; j++)
gsDomain[i][j] = ' ';
}
//初始化貪吃蛇活動區(qū)域的上下墻壁
for (int i = 0; i < 22; i++)
gsDomain[0][i] = gsDomain[21][i] = '-';
//初始化貪吃蛇活動區(qū)域的左右墻壁
for (int i = 1; i < 21; i++)
gsDomain[i][0] = gsDomain[i][21] = '|';
//初始化蛇身
for (int i = 1; i <= 3; i++)
gsDomain[1][i] = '*';
//初始化蛇頭
gsDomain[1][4] = '#';

int snake[2][100]; //記錄貪吃蛇每次出現(xiàn)的位置的坐標
for (int i = 0; i < 4; i++)
{
snake[0][i] = 1; //記錄貪吃蛇所在位置的x坐標
snake[1][i] = i + 1; //記錄貪吃蛇所在位置的y坐標
}
int head = 3, tail = 0, length = 4;

int beanX, beanY; //豆豆出現(xiàn)的位置
srand(time(0));
do
{
beanX = rand() % 20 + 1;
beanY = rand() % 20 + 1;
} while (gsDomain[beanX][beanY] != ' ');
gsDomain[beanX][beanY] = '*'; //豆豆

cout << "\n\n\t\t貪吃蛇游戲即將開始!\n";
long start;
int level = 1, moveSpeed = 1000;
for (int i = 3; i >= 0; i--)
{
start = clock();
while (clock() - start <= 1000){}
system("cls");
if (i)
{
cout << "\n\n\t\t進入游戲倒計時：" << i << endl;
}
else
display(gsDomain, level, moveSpeed);
}

char direction = 77; //貪吃蛇默認自動向右直線前進
while (true)
{
bool timeFlag = true;
int x, y;
start = clock();

//若時間超過自動前進時間或者鍵盤上有鍵按下則終止循環(huán)
while ((timeFlag = (clock() - start <= moveSpeed)) && !kbhit()){}

if (timeFlag)
{
//鍵盤上有鍵按下時讀取鍵盤輸入
getch();
direction = getch();
}

switch (direction)
{
//向上
case 72: x = snake[0][head] - 1, y = snake[1][head];
break;
//向下
case 80: x = snake[0][head] + 1, y = snake[1][head];
break;
//向左
case 75: x = snake[0][head], y = snake[1][head] - 1;
break;
//向右
case 77: x = snake[0][head], y = snake[1][head] + 1;
break;
default: cout << "\tGame Over!\n";
return 0;
}

if (x == 0 || x == 21 || y == 0 || y == 21)
{
//貪吃蛇觸碰到墻壁
cout << "\tGame Over!\n";
return 0;
}

if (gsDomain[x][y] != ' ' && !(x == beanX && y == beanY))
{
//貪吃蛇的蛇頭觸碰到蛇身或者蛇尾
cout << "\tGame Over!\n";
return 0;
}

if (x == beanX && y == beanY)
{
//吃豆豆
length++; //長度加1
if (length >= 8)
{
//游戲升級處理
length -= 8;
level++;
if (moveSpeed > 100)
moveSpeed -= 100;
}
gsDomain[snake[0][head]][snake[1][head]] = '*';
gsDomain[x][y] = '#';
head = (head + 1) % 100;
snake[0][head] = x;
snake[1][head] = y;
do
{
beanX = rand() % 20 + 1;
beanY = rand() % 20 + 1;
} while (gsDomain[beanX][beanY] != ' ');
gsDomain[beanX][beanY] = '*';

display(gsDomain, level, moveSpeed); //屏幕上顯示
}
else
{
//不吃豆豆
gsDomain[snake[0][tail]][snake[1][tail]] = ' '; //蛇尾前移一格
tail = (tail + 1) % 100;
gsDomain[snake[0][head]][snake[1][head]] = '*';
head = (head + 1) % 100;
snake[0][head] = x;
snake[1][head] = y;
gsDomain[x][y] = '#'; //蛇頭前移一格
display(gsDomain, level, moveSpeed); //屏幕上顯示
}
}

return 0;
}