What happens in memory when a C++ class is instantiated-Collection of common programming errors

Not sure of a good web site, but Inside The C++ Object Model is a pretty good book.

At least in the usual case, the member functions exist completely independent of any instance of the class. Instead, an instance of the class is a struct containing the (non-static) data members of the object. If the class has at least on virtual function, the object will also contain a pointer to a vtable, which is basically an array of pointers to functions.

When a member function is called, the address of that object is passed as a hidden parameter to the function (many compilers reserve a register just for it) and in the function it’s referred to as this.