#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <dos.h>
#include <string.h>

#define up 0
#define down 1
#define left 2
#define right 3

struct segment {int dir, x, y;};
struct segment segments[2520];
int key, length = 1;
int mx = 0, my = 0, i;


void graphic()
{
int gdriver = DETECT, gmode, errorcode;
initgraph (&gdriver, &gmode, "C:\\BC\\BGI");
errorcode = graphresult();
if (errorcode != grOk)
	{
	clrscr ();
	printf ("Graphics error: %s\n", grapherrormsg (errorcode));
	printf ("Press any key to halt");
	getch ();
	exit (1);
	}
}


void definedir()
{
if (key == 80)
		{
		segments[0].dir = up;
		}
if (key == 72)
		{
		segments[0].dir = down;
		}
if (key == 77)
		{
		segments[0].dir = right;
		}
if (key == 75)
		{
		segments[0].dir = left;
		}
}


void movehead()
{
if (segments[0].dir == up)
		{
		segments[0].x;
		segments[0].y++;
		}
if (segments[0].dir == down)
		{
		segments[0].x;
		segments[0].y--;
		}
if (segments[0].dir == right)
		{
		segments[0].x++;
		segments[0].y;
		}
if (segments[0].dir == left)
		{
		segments[0].x--;
		segments[0].y;
		}
setcolor (7);
circle (segments[0].x*10, segments[0].y*10, 5);
}


void movebody()
{
segments[length].x = segments[length-1].x;
segments[length].y = segments[length-1].y;
setcolor (0);
circle (segments[length].x*10,segments[length].y*10,5);

for (i = 1; i < length; i++)
	{
	segments[length-i].x = segments[length-1-i].x;
	segments[length-i].y = segments[length-1-i].y;
	setcolor (7);
	circle (segments[length-i].x*10,segments[length-i].y*10,5);
	}
}


void wallcrash()
{
if (segments[0].x*10 < 13 | segments[0].x*10 > 627 |
		segments[0].y*10 < 13 | segments[0].y*10 > 397)
		{
		setfillstyle(1,4);
		bar (10,400,629,479);
		setcolor (15);
		rectangle (12, 12, 627, 397);
		outtextxy (240, 440, "Snake has crashed");
		getch ();
		closegraph ();
		}
}


void selfcrash()
{
for (i = 1; i < length; i++)
	if (segments[0].x == segments[length-i].x && segments[0].y == segments[length-i].y)
		{
		setfillstyle(1,4);
		bar (0,400,639,479);
		setcolor (15);
		rectangle (12, 12, 627, 397);
		outtextxy (240, 440, "Snake has crashed");
		getch ();
		closegraph ();
		}
}


void checkmeal()
{
if (segments[0].x == mx && segments[0].y == my)
	{
	circle (mx*10, my*10, 5);
	setfillstyle (1, 0);
	floodfill (mx*10, my*10, 0);

	mx = random(62);
	my = random(39);
	if (mx < 2) mx=+2;
	if (mx == 62) mx--;
	if (my < 2) my=+2;
	if (my == 39) my--;

	setcolor (13);
	circle (mx*10,my*10,4);
	setfillstyle (1,13);
	floodfill (mx*10,my*10, 13);
	length++;
	}
}


void firstmeal()
{
mx = random(62);
my = random(39);
if (mx < 2) mx=+2;
if (mx == 62) mx--;
if (my < 2) my=+2;
if (my == 39) my--;
setcolor(13);
circle(mx*10,my*10,4);
setfillstyle(1,13);
floodfill(mx*10,my*10, 13);
}


int main()
{
graphic();

segments[0].x = 31;
segments[0].y = 20;
segments[0].dir = 0;

rectangle (13, 13, 627, 397);
getch();

randomize();
firstmeal();

while (key != 27)
{
if (kbhit()) key = getch();

movebody();
definedir();
movehead();
wallcrash();
selfcrash();
checkmeal();

delay(150);
}

getch();
closegraph();
}