A virtual function is a member function of a class, whose functionality can be over-ridden in its derived classes. It is one that is declared as virtual in the base class using the virtual keyword. The virtual nature is inherited in the subsequent derived classes and the virtual keyword need not be re-stated there. The whole function body can be replaced with a new set of implementation in the derived class
An abstract class is any class definition that contains at least one pure-virtual function. class AbstractClass { public: virtual void DoSomething()=0; // Pure-virtual. };
All virtual functions (including pure-virtual functions) are represented in italics. All non-virtual functions are represented normally. There is no differentiation between pure and non-pure virtual functions, however some people append "=0" to distinguish the pure-virtual functions.
...a function call.
Every C plus plus program that is a main program must have the function 'main'.
There is no such thing. When declaring a friend function only the explicitly-scoped friend is granted private access. The friend function may well be declared virtual within its own class but none of its overrides are granted access unless they are explicitly granted access.
An abstract class is any class definition that contains at least one pure-virtual function. class AbstractClass { public: virtual void DoSomething()=0; // Pure-virtual. };
Dynamic binding is achieved via virtual functions and the virtual table that is associated with every class that declares or inherits a virtual function. The virtual table (or v-table) maps every virtual function (including pure-virtual functions) to a function pointer that points to the most-derived overload. This makes it possible to invoke specific behaviour even when the runtime type of the object is unknown to the caller.
There is no such term as "building function" in C++.
All virtual functions (including pure-virtual functions) are represented in italics. All non-virtual functions are represented normally. There is no differentiation between pure and non-pure virtual functions, however some people append "=0" to distinguish the pure-virtual functions.
extensible means to enhance the program with new capabilities. In c++, extensibility can be achieved by using virtual function. now first we discuss what is virtual function in c++. " C++ virtual function is a member function of a class, whose functionality can be over-ridden in its derived classes. The whole function body can be replaced with a new set of implementation in the derived class." Through this u can be able to promote extensibility in your program by using Virtual function. Very simple concept.
...a function call.
yes,we can make function inline
Every C plus plus program that is a main program must have the function 'main'.
Control is returning to the caller of the function.
There is no such thing. When declaring a friend function only the explicitly-scoped friend is granted private access. The friend function may well be declared virtual within its own class but none of its overrides are granted access unless they are explicitly granted access.
method
It is the first function that gets called when the program is executed.