//	preproc.cc (<-- Euler.cc)

//	Demonstration of preprocessing directives

//	Pre: include file
#include <iostream.h>
#include <math.h>
//-------------------------------------------------------------
//	Pre: Alternative - Check whether M_PI is not defined
#ifndef M_PI
//	Pre: Define M_PI in that case
#define M_PI 3.14159
//	Pre: else-branch of alternative may follow
#else
//
//	Pre: End of alternative
#endif
//-------------------------------------------------------------
//	Pre: Define your own variables
#define MY_DEBUG
//	Pre: Undefine your own variable
//#undef MY_DEBUG
//	Pre: Define variable
#define SEE_PI 5
//-------------------------------------------------------------
//	Pre: Define your own macro
#define MAX(x,y)  (x > y ? x : y)
//-------------------------------------------------------------

int main()
{
 float e1;
 long long int i,n,m,j;
 
 n = 1000;
 m = 100000;
 
 for (i=1; i<=n; i++)
   {
     j = i*m;
     e1 = pow(1.0+1.0/j,double(j));
//	Pre: Use your own variable
#ifdef MY_DEBUG
     cout << "e - e1  = " << exp(1) - e1 << endl;
#endif
   }
 
 cout << endl << "e = " << exp(1) << endl;
 
//		M_E is the predefined Euler number  (/usr/include/math.h)
 cout << endl << "e = " << M_E - exp(1) << endl;

//		Check the value of preprocessor variable
#if (SEE_PI<5)
//		M_PI is the predefined PI number  (/usr/include/math.h) 
 cout << M_PI << " " <<sizeof(M_PI) << endl;
#endif
 
//	Use your own macro
 cout << "Max: " << MAX(1.45, 5.6) << endl;

 return 0;
}