/*
 **************************************************************************
 * Program name : 026_Inline_function (Version 1.00)                      *
 * Author       : Duck Wong                                               *
 * Language     : C / C++                                                 *
 * Compiler     : Boodshed Dec-C++ compiler Ver 3.95                      *
 * Computer     : PII350                                                  *
 * O/S          : Windows 98                                              *
 **************************************************************************
 * Version 1.00 : 2000/06/11 - first version                              *
 **************************************************************************
 * Description  : (a) Input the radius                                    *
 *                (b) Using an inline function to calculate               *
 *                    the surface area and volumn of a sphere             *
 *                (c) Try again ?                                         *
 **************************************************************************
*/
#include <iostream.h>
#include <stdlib.h>

const float PI=3.14159;                                              // Note (1)

inline float getarea(const float Radius)                             // Note (2)
  {return 4*PI*Radius*Radius*Radius;}                                // Note (3)
inline float getvolumn (const float Radius)                          // Note (2)
  {return 4*PI*Radius*Radius*Radius/3;}                              // Note (4)

int main()
{
 // part 1 : declaration
 float Radius, SurfaceArea, Volumn;
 char  Again;

 do {
     // part 2 : Repeat asking the size of the checkerboard pattern
     do
      {
       cout << "\nInput the radius of a sphere : ";
       cin  >> Radius;
       if (Radius<=0)
         cout << "\nMust be bigger than zero!\n";
      } while (Radius <= 0);

     // part 3 : Calculate the total surface area and volumn
     cout << "\nThe total surface area is " << getarea(Radius)
          << "\nThe volumn of this sphere is " << getvolumn(Radius)
          << "\n" << endl;

     // part 4 : try another number ?
     cout << "\aTry another number (Y/N) : ";
     cin  >> Again;
     cout << "\n";
    } while (Again=='Y' || Again=='y');
 cout << "\n" << endl;

 system("PAUSE");
 return 0;
}

/* Notes
   (1) The variable PI is defined as a "const" of data type float. This is a
       Global variable since it is defined before the function main.

   (2) The qualifier "inline" before the function's return type in the function
       definition "advises" the compiler to generate a copy of the function's
       code in place to avoid a function call.

       The keyword "const" on the parameter list of functions getarea and
       getvolumn tells the compiler that the functions does not modify the
       value of the variable Radius.

   (3) The total surface area of a sphere is : 4 X pi X Radius^3

   (4) The volumn of a sphere is : 4/3 X pi X Radius^3
*/