c++ - Calling assignment operator in copy constructor

Question

Are there some drawbacks of such implementation of copy-constructor?

Foo::Foo(const Foo& i_foo)
{
   *this = i_foo;
}

As I remember, it was recommend in some book to call copy constructor from assignment operator and use well-known swap trick, but I don't remember, why...

Answer 1

Yes, that's a bad idea. All member variables of user-defined types will be initialized first, and then immediately overwritten.

That swap trick is this:

Foo& operator=(Foo rhs) // note the copying
{
   rhs.swap(*this); //swap our internals with the copy of rhs
   return *this;
} // rhs, now containing our old internals, will be deleted