Inheritance and derivation (1)--the relationship between classes and classes, basic concepts of inheritance

1. The relationship between classes and classes

　　Has-a,uses-a and Is-a

Has-a contains relationships that describe a class consisting of multiple "part classes". Implementing a has-a relationship is represented by a class member, that is, the data member in one class is another class that has already been defined.

Uses-a one class to use the other class partially. Define a friend or object parameter delivery implementation through the interaction of member functions between classes.

The is-a mechanism is called "inheritance." The relationship is transitive and not symmetric.

classa{ Public:    voidFunca () {}intA;};//Class B has a member variable of Class A, B has A, Class B depends on Class Aclassb{ Public:    voidFUNCB () {} a A;};//the member method of Class C requires the formal parameter of Class A, C use a, Class C depends on Class Aclassc{ Public:    voidFUNCC (A *a) {}voidFUNCCC () {}};//Class D inherits from Class A, class D if it is inheriting Class A, Class D is Class A, Class C inherits from Class A, and the coupling is very highclassD: Publica{ Public:    voidFuncd () {cout<< a <<Endl; }};

2, the basic concept of inheritance

Inheritance and derivation (1)--the relationship between classes and classes, basic concepts of inheritance