Initial understanding of static and dynamic linking.

Polymorphism:

1. Static-Union polymorphism (compile-time polymorphism) implemented by overloads of functions, operators (the system compiles polymorphism based on the number of parameters)
2. Dynamic Union polymorphism (runtime polymorphism) through inheritance, virtual functions (when the runtime can implement objects and functions)C + +: Dynamic linking is implemented with the support of virtual function

Condition: A base class pointer to a derived class object or reference to a base class reference to a derived class object (calling a virtual function)

Dynamic linking:

1#include <iostream>2     using namespacestd; 3     classshape{4        Public:  5         void VirtualDraw () {cout<<"I am Shape"<<endl;}//This sets the draw to be a virtual function.6         voidFun () {Draw ();} 7     }; 8     classCircle Publicshape{9        Public:  Ten         voidDraw () {cout<<"I am Circle"<<endl;}//Although it is not stated that draw in the Circle class is a virtual function, circle actually inherits the virtual nature One     };  A     voidMain () { - Circle Oneshape;  - Oneshape.fun ();  the}

Without virtual, the program will output I am circle, because the virtual function is bound, if not, the output is I am shape; to get to the list, you have to learn the data structure and the Assembly,

In fact, the essence of virtual function is to make a data structure. that is, the virtual function table

Initial understanding of static and dynamic linking.