//  Duration class     (copyright 2003 Information Disciplines, Inc., Chicago) 
//  --------------

#ifndef DURATION
#define DURATION const Duration

 class Duration {
      double value;         //  Seconds

public:

static char* units;

//  Constructors
//  ------------

   Duration(DOUBLE s=0.0) : value(s) {}

//  The compiler will provide an acceptable copy constructor,
//  destructor, and assignment operator.


//  Arithmetic operators
//  --------------------

#define Class Duration
#include "Additive.hpp"

//  Relational operators
//  --------------------

friend bool operator== (Duration ls, Duration rs) 
            {return ls.value == rs.value;}
friend bool operator<  (Duration ls, Duration rs) 
            {return ls.value <  rs.value;}
       


};
 inline Duration& Duration::operator+= (DURATION rs){value += rs.value;}
 inline Duration& Duration::operator-= (DURATION rs){value -= rs.value;}
 inline Duration& Duration::operator*= (DOUBLE   rs){value *= rs;}
 inline Duration& Duration::operator/= (DOUBLE   rs){value /= rs;}
 
#undef Class
#endif