#include <graphics.h>
#include <slib.h>
#include <sio.h>
#include <conio.h>
#include <math.h>
#define ESC 0x1b;
#define MAXNUM 100

main()
{ char *buf;
char sign,sign1[MAXNUM] = {1},sign2[MAXNUM] = {1};
int i,size,a;
int x[MAXNUM],y[MAXNUM],r[MAXNUM][MAXNUM];
int gd = DETECT,gm;
clrscr();
printf("please input the number of ball you want:\n");
scanf("%d",&a);
registerbgidriver(EGAVGA_driver);
initgraph(&gd,&gm,"");
setcolor(YELLOW);
setfillstyle(SOLID_FILL,9);
rectangle(0,0,getmaxx(),getmaxy());
rectangle(1,1,getmaxx()-1,getmaxy()-1);
bar(2,2,getmaxx()-2,getmaxy()-2);
for(i = 8;i >=0;i --)
{ setcolor(i 7);
circle(11,getmaxy() - 11,i);
}
size = imagesize(2,getmaxy() - 20,20,getmaxy() - 2);
buf = malloc(size);
getimage(2,getmaxy()-20,20,getmaxy() - 2,buf);
for(i = 8;i >= 0;i --)
{ setcolor(9);
circle(11,getmaxy() - 11,i);
}
randomize();
for(i = 0;i < a;i )
{ x[i] = random(600) 20;
y[i] = random(400) 32;
}

while(1)
{ if(kbhit())
{ sign = getch();
if(sign == 0x1b)
{ free(buf);
break;
}
}
else
{
for(i = 0;i < a;i ){
putimage((sign1[i] == 1 ? x[i] : x[i] --),
(sign2[i] == 1 ? y[i] : y[i] --),buf,COPY_PUT);

if(x[i] > getmaxx() - 21)
sign1[i] = 0;
if(x[i] < 3) sign1[i] = 1;
if(y[i] > getmaxy() - 21)
sign2[i] = 0;
if(y[i] < 3) sign2[i] = 1;}
}
}
free(buf);
closegraph();
return 0;
}