How virtual functions can be implemented in c++?, C/C++ Programming

How virtual functions can be implemented in C++?

 

 

Posted Date: 3/15/2013 6:31:11 AM | Location : United States





A: Virtual functions are implemented by a table of function pointers, called vtable. There is one entry in table per virtual function in class. This table is formed through the constructor of the class. While a derived class is constructed, its base class is constructed _rst that creates the vtable. If the derived class overrides any of base classes virtual functions, those entries into the vtable are overwritten through the derived class constructor. It is why you must never call virtual functions from a constructor: since the vtable entries for the object might not have been set up through the derived class constructor still, so you might end up calling base class implementations of those virtual functions

Posted by | Posted Date: 3/15/2013 6:31:40 AM

A: Virtual functions are implemented by a table of function pointers, called vtable. There is one entry in table per virtual function in class. This table is formed through the constructor of the class. While a derived class is constructed, its base class is constructed _rst that creates the vtable. If the derived class overrides any of base classes virtual functions, those entries into the vtable are overwritten through the derived class constructor. It is why you must never call virtual functions from a constructor: since the vtable entries for the object might not have been set up through the derived class constructor still, so you might end up calling base class implementations of those virtual functions

Posted by | Posted Date: 3/15/2013 6:32:48 AM


Related Discussions:- How virtual functions can be implemented in c++?, Assignment Help, Ask Question on How virtual functions can be implemented in c++?, Get Answer, Expert's Help, How virtual functions can be implemented in c++? Discussions

Write discussion on How virtual functions can be implemented in c++?
Your posts are moderated
Related Questions
#At a shop of marbles, packs of marbles are prepared. Packets are named A, B, C, D, E …….. All packets are kept in a VERTICAL SHELF in random order. Any numbers of packets with the


I am having trouble declaring a variable and returning a value from my function.


program to check whether a given point lies inside a rectangle or not

#questionHi, I am looking for help with the assignment, can you help..

b) The static keyword let a variable to maintain its value among distinct function calls. If the value of a static variable alters while the variable has been accessed, variable

write a c++ program for minimum shelf downloads

how to create database of faculty database......... send me with program

Using Figure 10.2 as a model, illustrate the result of each operation in the sequence ENQUEUE.Q; 4/, ENQUEUE.Q; 1/, ENQUEUE.Q; 3/, DEQUEUE.Q/, ENQUEUE.Q; 8/, and DEQUEUE.Q/ on an i