First, The core idea of object-oriented programming (Object-oriented programming) is data abstraction, inheritance, dynamic binding . With data abstraction, you can decouple the interface of a class from implementation, use inheritance, and make it easier to define new classes that are similar but not identical to other classes, using dynamic binding, to some extent ignoring the differences of similar classes, and using their objects in a uniform way. The function of
Directory: http://www.cnblogs.com/WuCountry/archive/2008/11/15/1333960.html[Do not provide illustrations. You are advised to download the source book from the Internet]
5.9. Virtual Devices Virtual DeviceA virtual device is an internal action built on top of one or more real devices. the association between virtual d
The memory size calculation of the class in the case of virtual inheritanceWhen there are multiple virtual functions in each base class, and in the case of virtual inheritance, how the memory is allocated and how the class size is computed, the following example illustrates:#include using namespace Std;Class A{Publicint A;vir
Virtual functions in C + + (virtual function)
1. Introduction
Virtual functions are the mechanisms used in C + + to implement polymorphism (polymorphism). The core idea is to access the function defined by the derived class through the base class. Let's say we have the following class hierarchy:
Class A
{
Public
virtual
In this paper, the usage of virtual function and pure virtual function in C + + is deeply analyzed, which is very important for learning and mastering object-oriented programming. The specific contents are as follows:
First, the core idea of object-oriented programming (object-oriented programming) is data abstraction, inheritance and dynamic binding . With data abstraction, you can detach the interface of
First, emphasize a concept.Defining a function as a virtual function does not mean that the function is not implemented.It is defined as a virtual function to allow the base class pointer to call this function of the subclass.Defining a function as a pure virtual function means that the function is not implemented.A pure virt
First, emphasize a concept.Defining a function as a virtual function does not mean that the function is not implemented.It is defined as a virtual function to allow the base class pointer to call this function of the subclass.Defining a function as a pure virtual function means that the function is not implemented.A pure virt
Can a destructor be a pure virtual function in C + +?It is well known that in the process of implementing polymorphism, the destructor of the base class is generally set virtual so that it delete can be called in a multi- state chain . Then can the destructor be set to pure virtual?class CBase{ public: CBase() { printf("CBase()\n");
Class Object Memory layout, virtual functions, virtual inheritance and multi-inheritance Implementation Mechanism
1. classes without inheritance relationships
2. Single inheritance
2.1 single-layer inheritance
2.2 multi-Inheritance
3. Multi-Inheritance
1. classes without inheritance relationships
Class A and Class B are known. Class A represents A class without virtual
Preparatory work1. VS2012 use command line options to view the memory layout of an objectMicrosoft Visual Studio provides the option for users to display the layout of C + + objects in memory:/d1reportsingleclasslayout. It's easy to use, just click on the "Visual properties " button under the [Project P] option. Switch to the CPP file in the directory where you can enter the following commandC1 [Filename].cpp /d1reportsingleclasslayout[classname]Where [Filename].cpp is the CPP file where the cl
If there is no virtual function virtual inheritance is only a nightmare, then this is the real purgatory. The most complex inheritance level in C + + in the implementation of the VS actually I do not fully understand, some of the hard-hitting also calculate the Microsoft implementation method, as for some tricky way to realize I also can not think of any reason to explain it, but also only know its why not
From: http://www.cnblogs.com/chio/archive/2007/09/10/888260.html
I. Virtual destructor
We know that in order to correctly call the object's destructor, a top-level class with a hierarchy is generally required to define its destructor as a virtual function. When deleting an abstract class pointer, you must use a virtual function to find the true destructor.
For ex
The Dalvik virtual machine relies on the underlying POSIX-compliant operating system, which can simply complete process isolation and thread management. It has efficient use of memory and high performance on Low-speed CPUs. Each Android application has a separate Dalvik virtual machine instance at the bottom, and its code is executed with the virtual machine inte
Introduction??This chapter is about the memory area of the Java virtual machine can be divided into several parts, the book can be divided into five parts: heap, Stack, program counter, method area, local method stack??Where the heap contains an instance of the object??And often said the basic data type, and the object reference is stored in the stack, in fact, is actually stored in the virtual machine stac
Recently, I read the memory layout of objects with virtual inheritance levels in the inside C ++, and found that the implementations in different compilers are different. Therefore, I explored it myself. The result is as follows:First, let's talk about the GCC compiler.It is easy to implement. No matter whether it is virtual inheritance or not, GCC shares the virtual
Virtual functions are an important concept in Object-Oriented C ++. Because it fully embodies the inheritance and polymorphism features in object-oriented thinking, it is widely used in C ++. For example, in Microsoft's MFC class library, you will find that many functions have virtual keywords, that is, they are all virtual functions. It is no wonder that
SummaryIn this paper, we first describe the definition of virtual function and pure virtual function, then analyze and compare the difference and relation (DWS).Body
1) What is the difference between virtual function and pure virtual function?
Virtual Functions
, doe
??This phrase feels like the nature of the GC .??????1. Procedure Counter (program Counter Register)??A program counter is a small amount of memory space that acts as a line number indicator of the bytecode that is being executed by the current thread . The bytecode interpreter works by changing the value of this counter to select the next byte-code instruction to execute, and the basic functions such as branching, looping, jumping, exception handling, thread recovery, and so on, need to rely on
Concept:
Virtual functions (virtual function) are implemented by a virtual function table (virtual table), referred to as v-table.
The role of learning virtual functions:
Understand the mechanism of C + + to implement polymorphism, solve the problem of inheritance and covera
Recently, I read the memory layout of objects with virtual inheritance levels in the inside C ++, and found that the implementations in different compilers are different. Therefore, I explored it myself. The result is as follows:
First, let's talk about the GCC compiler.
It is easy to implement. No matter whether it is virtual inheritance or not, GCC shares the virt
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