Question

This is my method of adding 2 Duration objects together in the format (HH,MM,SS).

    inline ostream& operator<<(ostream& ostr, const Duration& d){
      return ostr << d.getHours() << ':' << d.getMinutes() << ':' << d.getSeconds();
    }

    Duration operator+ (const Duration& x, const Duration& y){
        if ( (x.getMinutes() + y.getMinutes() >= 60) && (x.getSeconds() + y.getSeconds() >= 60) ){
           Duration z( (x.getHours() + y.getHours() + 1), (x.getMinutes() + y.getMinutes() + 1 - 60), (x.getSeconds() + y.getSeconds() - 60) );
           return z;
        }
        else if (x.getSeconds() + y.getSeconds() >= 60){
           Duration z( (x.getHours() + y.getHours()), (x.getMinutes() + y.getMinutes() + 1), (x.getSeconds() + y.getSeconds() - 60) );
           return z;
        }
        else if (x.getMinutes() + y.getMinutes() >= 60){
           Duration z( (x.getHours() + y.getHours() + 1), (x.getMinutes() + y.getMinutes() - 60), (x.getSeconds() + y.getSeconds()) );
           return z;
        }
        else{
            Duration z( (x.getHours() + y.getHours()), (x.getMinutes() + y.getMinutes()), (x.getSeconds() + y.getSeconds()) );
            return z;
        }
    }

In my main method i have:

  Duration dTest4 (01,25,15);
  Duration result = dTest4+dTest4;
  cout << result << endl;

Unfortunately when i run the program i get this error:

  error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class Duration const &)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@ABVDuration@@@Z) referenced in function _wmain 1>C:\Users\...exe : fatal error LNK1120: 1 unresolved externals

I want to be able to add two times together in individual entities. Ie. The hours together, then the minutes, then the seconds. Hence the if-else to deal with when 2 sets of minutes exceed the 60min cap of an hour…

Any help would be appreciated.

Answer 1

The problem is here: cout << result << endl;
You haven’t defined an overloaded version of std::ostream& operator<< for writing your Duration object to an ostream. Something like this should do it:

std::ostream& operator<<(std::ostream& os, const Duration& rhs)
{ 
os << "Hours: <" << hours_ << ">, ";  
os << "Minutes: <" << minutes_ << ">, "; 
os << "Seconds: <" << seconds_ << ">"; 
return os; 
}