I have some code where I am overloading the insertion and extraction operators. Even though I have declared both overloaded operators to be friends of my class I am getting an exception saying that the overloaded operator doesn't have access to private members of my class.
Start.h
[source lang=cpp]
#ifndef IGES_SECTION_START_H_
#define IGES_SECTION_START_H_
#include <iosfwd>
#include <string>
namespace IGES
{
namespace Section
{
class Start
{
public:
friend std::ostream & operator<<(std::ostream & stream, Start const & start);
friend std::istream & operator>>(std::istream & stream, Start const & start);
protected:
private:
std::string data;
};
};
};
std::ostream & operator<<(std::ostream & stream, IGES::Section::Start const & start);
std::istream & operator>>(std::istream & stream, IGES::Section::Start const & start);
#endif
Start.cpp
[source lang=cpp]
typedef std::map<IGES::Datatype::Integer, std::string> map_type;
std::istream & operator>>(std::istream & stream, IGES::Section::Start const & start)
{
std::string line;
map_type lines;
do
{
std::ios_base::streampos startOfLine = stream.tellg();
std::getline(stream, line);
if(line[72] == 'S')
{
if(line.size() != 80)
{
throw new std::invalid_argument("start lines must be 80 charaters long");
}
IGES::Datatype::Integer lineNumber = boost::lexical_cast<IGES::Datatype::Integer>(line.c_str() + 72);
lines.insert(std::make_pair(lineNumber, std::string(line.begin(), line.begin() + 72)));
}
else
{
stream.seekg(startOfLine);
}
}while(line[72] == 'S');
for(map_type::const_iterator i = lines.begin(); i != lines.end(); ++i)
{
start.data.append(i->second);
}
return stream;
}
The error is on the line that says: start.data.append(i->second); It says that I can't access private member data of class Start.
Am I misusing friend? I very rarely have need of it, so I'm not nearly as familiar with its intricacies as other parts of C++.
