/*--------------------------------------------------
created by st10 at Thu Oct 13 14:05:31 PST 2016
--------------------------------------------------*/
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include "circ_area.h"
using namespace std;


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

 Examples: circ_area(1) == 3.14159
          circ_area(10) == 314.159
--------------------------------------------------*/

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