Some Notes on C++ Constructors

The followings are automatically added to every class, if we do not write our own.
- copy constructor
- assignment operator
- a constructor without without any parameter
A copy constructor may be called
- when an object of the class is returned by value
- when an object of the class is passed (to a function) by value as an argument
- when an object is constructed based on another object of the same class
- when compiler generate a temporary object
Unlike new, malloc() doesn’t call constructor.
Object must be passed by reference in copy constructors.
We must use initializer list in a constructor when
- there is a reference variable in class
- there is a constant variable in class
- there is an object of another class. And the other class doesn’t have default constructor.
If a class has a constructor which can be called with a single argument, then this constructor becomes conversion constructor because such a constructor allows automatic conversion to the class being constructed. A conversion constructor can be called anywhere when the type of single argument is assigned to the object.

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