assign and operator=

1、是在思考virtual operator=时，在 CppCoreGuidelines C.60: Make copy assignment non-virtual, take the parameter by const&, and return by non-const&

中，有这样的描述:

Alternatives: If you think you need a virtual assignment operator, and understand why that's deeply problematic, don't call it operator=. Make it a named function like virtual void assign(const Foo&). See copy constructor vs. clone()

这引发了我对assign and operator=的思考

stackoverflow std::string::assign vs std::string::operator=