virtual constructor

From the storage space point of viewThe virtual function corresponds to a vtable pointer to a virtual function table, which we all know, but this vtable pointer is actually stored in the object's memory space. The problem comes out, if the constructor is virtual, it needs vtable to be called through, but the object has

The reason the constructor cannot be declared as a virtual function: 1, the so-called virtual function is a polymorphic case only executes one, and from the concept of inheritance, always first constructs the parent class object, then can make the child class object, if the constructor is set to the

Why cannot an inline function, constructor, or static member function be a virtual function? 1> inline functions Inline functions are expanded during compilation, and virtual functions are dynamically integrated during runtime. Therefore, they cannot be defined as virtual functions. 2>

Preface This article will explain the mistakes that a novice C ++ programmer often makes-using virtual functions in constructor/destructor, and analyzing the cause of the error and how to avoid it. Error cause First, let's assume that we use a class that implements transaction as the parent class, then a class that implements purchase, and a class that implements sale as its subclass. During initialization

Constructor: allocates storage space for an object to initialize it;Destructor: performs the final scanning at the end of the object's life cycle and releases the memory allocated by the constructor; The constructor cannot be a virtual function: Your own words: [virtual

function on the blog to see an article "FxCop constructorsshouldnotcallbaseclassvirtualmethods norms," the original: http://blog.csdn.net/xamcsdn2/ Archive/2004/08/11/71766.aspx Quite interested in writing a piece of code research (the estimate is still not a study, just explore it) a bit. The code is as follows. Using System; Namespace Test_console { ??? Class BaseClass ??? { ??????? public int count = 0; ??????? Public BaseClass () ??????? { ??????????? Console.WriteLine ("Call BaseClass

Each time you create a transaction object, you must create an appropriate record in the audit log. The following is a reasonable practice: Class transaction{Public:Transaction (){Init ();}Virtual void logtransaction () const {STD: cout Protected: PRIVATE:Void Init (){Logtransaction ();}}; Class buytransaction: Public transaction{Public:Buytransaction (): A (5 ){}Virtual void logtransaction () const {STD: co

Copy constructorIf you do not define a copy constructor, the compiler will automatically generate a copy constructor, but there is a limit to the copy constructor.In general, this copy constructor is directly copied according to the bit, but in some cases this initialization is problematic, in the special four cases is problematic, in case of problems, can be ill

First, I wrote a constructor with the virtual Class A, the code is as follows:Class A{public:virtual A () {}};Run Result: (I was running under VS)650) this.width=650; "Src=" Http://s5.51cto.com/wyfs02/M00/8C/4E/wKiom1hp9s6C6s6qAABXFQCBqKI219.png-wh_500x0-wm_3 -wmp_4-s_4041109755.png "title=" 1.png "alt=" Wkiom1hp9s6c6s6qaabxfqcbqki219.png-wh_50 "/>You can see that this code compiles with a problem.Why can't

The following code is compiled with an error because the constructor cannot be a virtual function.1 classStudent {2 Public:3 VirtualStudent ()4 {5 This->dwno =0;6 }7 8 Private:9 intDwno;Ten};So why can't a constructor be a virtual function?Here you need to know a concept, that is, the

Environment: XPSP3 VS2005Today the black general to the candidate out of a C + + constructor call virtual function, the specific topic is more complex than the title, the general situation can see the following code:[CPP]View PlainCopy Class Base { Public Base () { Fuction (); } virtual void fuction () { cout "base::fuction" } };

The constructor cannot be a virtual function. When you create a derived class object, the constructor of the derived class is called instead of the constructor of the base class, and then the constructor of the derived class uses a const