Thread: drawing circle in VGA mode

oke heres the code that defines the circle

Code:

int circle(int color,int centerx,int centery,int r)
{
	int x,y;
	float a;
	float pi=3.1415927;
	for(a=0;a<2*pi;a=a+pi/180){
															x=cos(a)*r+centerx;
															y=sin(a)*r+centery;
															setpix(color,x,y);
															}

	return 0;
	}

and this is the code that draws 100 circles in different colours

Code:

time_t t;
  srand((unsigned) time_t(&t));
  for(i=0;i<100;i++){
						  color=rand()%15;
						  circle(color,160,100,100-i);
						  
						  }

now my problem is that this is going very ...and i mean very slow
i dont think my comp is the problem but rather the code that eats memory....
Any suggestions on how to make this go faster???