Function must have exactly one argument

Question

I\'ve not coded in C++ for a long time and I\'m trying to fix some old code.

I\'m geting the error:

TOutputFile& TOutputFile::operator<<(TOutpu         


        

Answer 1

Operator overloaded functions which are defined as member functions accept only one parameter. In case of overloading << operator, more than one parameter is required. Making it a friend function solves this issue.

class {
    ...
    friend TOutputFile &operator<<(TOutputFile &OutFile, const T &a);
    ...
};

template
TOutputFile &operator<<(TOutputFile &OutFile, const T &a) {
    *OutFile.FFileID << a;
    return OutFile;
}

A function marked as friend will allow that function to access private member of the class to which it is a friend.