I have a complex object that I want to be able to pass into a std::ostringstream
with the <<
operator just like a string or int. I want to give the ostringstream the object's unique id (int) and/or name (string). Is there an operator or method I can implement in my class to allow this to work?
Define an operator overload in the same namespace as your class:
template<typename charT, typename traits>
std::basic_ostream<charT, traits> &
operator<< (std::basic_ostream<charT, traits> &lhs, Your_class const &rhs) {
return lhs << rhs.id() << ' ' << rhs.name();
}
If the output function needs access to private members of your class then you can define it as a friend function:
class Your_class {
int id;
string name;
template<typename charT, typename traits>
friend std::basic_ostream<charT, traits> &
operator<< (std::basic_ostream<charT, traits> &lhs, Your_class const &rhs) {
return lhs << rhs.id << ' ' << rhs.name;
}
};
Note that this does not result in a member function, it's just a convenient way to declare and define a friend function at once.
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