Effective C++ by Scott Meyers book review

Introduction

• Copy Constructor
  • Used to initialize an object with a different object of the same type
  • Defines how an object is passed by value
• Copy assignment operator
  • Used to copy the value from one object to another of the same type

class Widget {
public:
    Widget(const Widget& rhs);    // Copy Constructor
    Widget& operator=(const Widget& rhs);    // Copy assignment operator
};

Widget w1;
Widget w2(w1);    // invoke copy constructor
w1 = w2;          // invoke copy assignment operator

Widget w3 = w2    // invoke copy constructor

• The parameter w is passed by value, so aWidget is copied into w.
  • The copying is done by copy constructor.
  • Pass-by-value == “call the copy constructor”
    • But Pass-by-reference-to-const is typically a better choice

bool hasAcceptable(Widget w);

Widget aWidget;
if(hasAcceptable(aWidget))...