C++ float type floating point variables

#include <iostream>
using namespace std;
int main()/*from  ww  w . j ava  2  s . c  om*/
{
   float rad;                           //variable of type float
   const float PI = 3.14159F;           //type const float
   cout << "Enter radius of circle: ";  //prompt
   cin >> rad;                          //get radius
   float area = PI * rad * rad;         //find area
   cout << "Area is " << area << endl;  //display answer
   return 0;
}