advance c++ (1)

• copy constructor
• copy assignment operator
• deconstructor
• default constructor

the compiler will automatically generate for every class

/* Summary of disallowing functions
 * 
 * 1. c++ 11: f() = delete
 * 2. c++ 03: declare the function to be private, and not define it
 * 3. private destructor: stay out of stack 
 */ 
Foo(const Foo& rhs) = delete