/*--------------------------------------------------
created by st10 at Fri Oct 15 08:54:05 PDT 2010
--------------------------------------------------*/
#include <iostream>
#include <cmath>
#include "circ_area.h"
using namespace std;


/*--------------------------------------------------
 signature: circ_area : double -> double
 purpose: expects the radius of a circle and produces
         that circle's area

 Examples: circ_area(0) == 0
          abs(circ_area(10) - 314.159) < 0.001
--------------------------------------------------*/

double circ_area(double radius)
{
    return PI * radius * radius;
}