Collision Of 2 balls!!

#include
#include
#include
#include
#define pi 3.14285
#define round(a)((int)(a+0.5))
int i,j;

void parcir(int xc,int yc,float r,int sang,int eang,int col)
{ int k;
float x,y;

for(k=sang;k { x=xc+r*cos(pi*k/180);
y=yc+r*sin(pi*k/180);
putpixel(round(x),round(y),col);
}
}

void drawcir(int x,int y,float r,int sang)
{ int k=0;
int eang;
eang=sang+120;
while(k!=3)
{
parcir(x,y,r,sang,eang,(k+1));
sang=eang;
eang+=120;
k++;
}

}
void main()
{int gd,gm; int x1=20,x2=20,xc1=200,xc2=600;
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"..\\bgi");
i=0;
while((xc2-xc1)>40)
{ delay(100);
cleardevice();
drawcir(xc1,200,20,i);
xc1+=x1;
i++;
drawcir(xc2,200,20,j);
xc2-=x2;
j--;

}
cleardevice();
drawcir(xc1,200,20,i);
drawcir(xc2,200,20,j);
delay(100);
i=0;j=0;
while(xc1!=10)
{ delay(100);
cleardevice();


drawcir(xc1,200,20,i);
xc1-=x1;
i--;
drawcir(xc2,200,20,j);
xc2+=x2;
j++;

}
getch();
}