Inheritance & Destructors

Constructing/Destructing Object built/destroyed in layers Base class constructed Derived class constructed Geometric Object Circle

Constructing/Destructing Object built/destroyed in layers Base class constructed Derived class constructed Derived class destroyed – clean up after itself Geometric Object

Constructing/Destructing Object built/destroyed in layers Base class constructed Derived class constructed Derived class destroyed – clean up after itself Base class destroyed – clean up after itself

Example Simple list has array of ints LessSimpleList is a SimpleList with one extra char on heap Each new has a matching delete

Example Base created Derived created Derived destroyed Base destroyed 1 5 3 2 4

Example Base created Derived created Derived destroyed Base destroyed 1 5 3 2 4

Copy Constructor Issue No copy constructor = trouble:

Copy Constructor Issue Copying child class defaults to no-arg construction of parent:

Copy Constructor Fix Child copy ctor should explicitly call parent one

Assignment Operator Assignment operator also needs to call parent version:

Virtual Messiness Also need to worry about virtual dispatch to handle: SimpleList* list = new LessSimpleList(); delete list; Fixes: Virtual destructor Child classes need to override parent Copy/Assignment https://stackoverflow.com/questions/669818/virtual-assignment-operator-c