Overloading operator << - C++

Question

Background

I have a container class which uses vector internally. I have provided a method AddChar(std::string) to this wrap

Answer 1

The operator is not correctly overloaded here. There is no reason to make the operator a friend since it can be a member of the class. Friend is for functions which are not actual members of the class (such as when overloading << for ostream so the object can be output to cout or ofstreams).

What you actually want the operator to be:

ExtendedVector& operator<<(const std::string str){
    AddChar(str);
    return *this;
}

It is usually considered bad practice to overload operators in a way that has them do something than they do normally. << is normally bit shift, so overloading it this way can be confusing. Obviously STL overloads << for "stream insertion" and so along with that it might make sense to overload it for your use in a similar way. But that doesn't seem like what you're doing, so you probably want to avoid it.

There are no performance issues since operator overloading is the same as a regular function call, just the call is hidden because it is done automatically by the compiler.