Item 5: Know What Functions C++ Silently Writes and Calls

The 4 bread-and-butter functions: default constructor, copy constructor, copy assignment operator, and destructor.

• Default constructor is generated if no constructor is declared.
• Copy constructor and copy assignment operator are generated when it makes sense/unambiguous (e.g., no reference-typed member and no const member).
• Destructor is generated (and declared virtual if needed) if no destructor is declared.