Passing istream into a function

Nagilum picture Nagilum · Jan 27, 2013 · Viewed 10k times · Source

I am making a game-type program similar to the idea of pokemon. We have a tournament class that keeps track of several teams(its own class) which consists of pets(its own class) with different kinds of pets being subclasses of CPet.

We are attempting to pass a file name into main, from main pass that file name into the Tournament class. In the Tournament class we open the file with:

 14 //Construct a tournament
 15 CTournament::CTournament(const char *Filename){
 16         //opening file
 17         ifstream inFile(Filename, ios::in);
 18         if(inFile.bad()){
 19                 cout << "File error" << endl;
 20                 return ;
 21         }
 22          //get Teamlist for tournament
 23          while(!(inFile.eof())){
 24                  CTeam* temp = new CTeam;
 25                  temp->ParseTeam(inFile);
 26 
 27                  TeamList.push_back(temp);
 28          }
 29 }

Here we pass inFile into CTeam.ParseTeam which looks like:

     30 void CTeam::ParseTeam(std::istream in){
     31   string readline;
     32   getline(in, readline);
     33   this->TeamName = readline;
     34   while(!(in.eof())&&(readline != " " || readline != "/n"))
     35   {
     36           getline(in, readline);
     37           this->Parse(readline);
     38   }
     39 }

and we are getting the error:

In file included from /usr/include/c++/4.4/ios:39,
                 from /usr/include/c++/4.4/ostream:40,
                 from /usr/include/c++/4.4/iostream:40,
                 from CTournament.h:11,
                 from CTournament.cpp:8:
/usr/include/c++/4.4/bits/ios_base.h: In copy constructor 'std::basic_ios<char, std::char_traits<char> >::basic_ios(const std::basic_ios<char, std::char_traits<char> >&)':
/usr/include/c++/4.4/bits/ios_base.h:790: error: 'std::ios_base::ios_base(const std::ios_base&)' is private
/usr/include/c++/4.4/iosfwd:47: error: within this context
/usr/include/c++/4.4/iosfwd: In copy constructor 'std::basic_istream<char, std::char_traits<char> >::basic_istream(const std::basic_istream<char, std::char_traits<char> >&)':
/usr/include/c++/4.4/iosfwd:53: note: synthesized method 'std::basic_ios<char, std::char_traits<char> >::basic_ios(const std::basic_ios<char, std::char_traits<char> >&)' first required here 
CTournament.cpp: In constructor 'CTournament::CTournament(const char*)':
CTournament.cpp:25: note: synthesized method 'std::basic_istream<char, std::char_traits<char> >::basic_istream(const std::basic_istream<char, std::char_traits<char> >&)' first required here 
CTournament.cpp:25: error:   initializing argument 1 of 'void CTeam::ParseTeam(std::istream)'

I know there is a similar question about this where he did not include fstream. We have included it in both header files.

I thought maybe it was a problem of not passing the correct type into PraseTeam, but I could not find anything very specific on how else to pass the file into ParseTeam to verify whether I was doing it correctly or not.

Thanks in advance.

Answer

Sergey Kalinichenko picture Sergey Kalinichenko · Jan 27, 2013

You need to pass the stream by reference, because streams are not generally copyable:

void CTeam::ParseTeam(std::istream &in)