// volume.cpp
//
// Write a C++ program to ask the user to
//   input a radius value and a height.
//
// Calculate (and output) the volume of a cylinder.
//
// Next, change it to a cone

#define PI 3.1415927

#include <iostream>
#include <cmath>
// pow()  abs()  sin()  cos()  tan()  log()  floor()  ceil()
// round()  trunc()  sqrt()
using namespace std;

int main()
{
    double radius, height;
    double volume_cylinder;

    cout << "This program calculates the volume of a cylinder\n"
         << "and a cone.\n\n";

    cout << "Enter radius: ";
    cin >> radius;
    
    cout << "Enter height: ";
    cin >> height;

    // square the radius:
    double s = pow( radius, 2 );

//    volume_cylinder = PI * radius * radius * height;
    volume_cylinder = PI * pow( radius, 2 ) * height;
    cout << "Volume of the cylinder is " << volume_cylinder << endl;

    double volume_cone;
//    volume_cone = (1 / 3) * volume_cylinder;
    //   1 / 3    ==> 0  !!!!!
    // int / int  ==> int     (integer division)
    //
    //   2 / 3  ==>  0

    volume_cone = volume_cylinder / 3;
    //  double / int   ==>  double / double ==> double

    cout << "Volume of the cone is " << volume_cone << endl;

    return 0;
}