Talking about the virtual functions inherited in c ++

Virtual functions in c ++ inheritance 

C ++ is an obvious manifestation of an object-oriented programming language. It supports the Inheritance Mechanism. There are many inheritance types in c ++, there are different classification methods based on different categories. For example, the number of base classes can be divided into multi-inheritance and single-inheritance, and the access permission can be divided into public inheritance, protected inheritance, and private inheritance, virtual inheritance and non-virtual inheritance can be divided into virtual inheritance and non-virtual inheritance. Of course, the classification standards here are overlapping parts. For example, non-virtual inheritance can be divided into single inheritance and multi-inheritance. We will discuss the virtual functions here, so we will discuss and analyze them from the virtual and non-virtual inheritance aspects.

1. non-virtual inheritance: single inheritance and multi-inheritance. Let's look at an example:

 1 class base1 2 { 3 public: 4  virtual void f(){} 5   virtual void h(){} 6 }; 7 class base2 8 { 9 public:10  virtual void g(){}11 };12 class derive1:public base113 {14 public:15 virtual void f(){}16 virtual void f1(){}17 }18 class derive2:public base1,public base219 {20 public:21  virtual void f(){}22  virtual void g(){}23  virtual void g1(){}24 };

 

Create four objects: base1 b1; base2 b2; derive1 d1; derive2 d2; learn the virtual function table in the dashboard of c ++, the following table lists the virtual functions of each class in the inheritance system. The virtual functions of base1 are as follows: vptr --> base1: f base1 :: h // vptr is the pointer to the virtual function table of the class. --> indicates that it points to a table. The following content is the virtual function table of base2 in the table: the virtual function table of vptr --> base2: g // derive1 is as follows: vptr --> derive1: f base1: h derive1: fderive2: vptr1 --> derive2: f base1: h derive2: g1 // base1vptr2 --> derive2: g // base2 view the following table of virtual functions on the windows Development Platform: the host environment is win7 + vs2013 (not completely displayed). In debugging mode: 2. virtual Replication Virtual inheritance is a technology introduced in Multi-inheritance. The analysis and discussion of virtual inheritance is not the focus of this article. If you do not know it, you can view related c ++ books, the following describes virtual functions in virtual. 1 class base1 2 {3 public: 4 virtual void f () {} 5}; 6 class base2 7 {8 public: 9 virtual void g () {} 10 }; 11 class derive1: virtual public base112 {13 public: 14 virtual void f () {} 15 virtual void f1 () {} 16} 17 class derive2: virtual public base1, virtual public base218 {19 public: 20 virtual void f () {}21 virtual void g () {}22 virtual void g1 () {}23 };View Code

 

Through vs2013 to view the virtual function table is as follows: This article refer to the well-known technology blogger left ears mouse in the csdn blog, blog address: http://blog.csdn.net/haoel/article/details/1948051 welcome everyone to discuss and exchange, welcome to reprint, do not use it for commercial purposes. All Rights Reserved. The source must be indicated for reprinting.