What is the use of virtual keyword in inheritance?
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use of virtual keyword in inheritance-------> Multiple inheritance in C++ is a powerful, but tricky tool, that often leads to problems if not used carefully. This article will teach you how to use virtual inheritance to solve some of these common problems programmers run into
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The 'virtual' keyword enables polymorphism such that you actually override functions. Because enheriting any function is not overriding, in C++ 'virtual' keyword is must to implement dyanamic polymorphism. Here is C++ example: struct Base { virtual void foo() {} }; struct Derived : Base { ...
read more The 'virtual' keyword enables polymorphism such that you actually override functions. Because enheriting any function is not overriding, in C++ 'virtual' keyword is must to implement dyanamic polymorphism. Here is C++ example: struct Base { virtual void foo() {} }; struct Derived : Base { virtual void foo() {} // * second `virtual` is optional, but clearest }; Derived d; Base& b = d; b.foo(); This invokes Derived::foo, because this now overrides Base::foo — your object is polymorphic. read less
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Virtual keyword is used in inheritance to avoid ambiguity that may rise especially during multiple inheritance. Let me explain it with an example. Consider a class "Point" that reads and plots (x,y) co-ordinates. A new class "Line" that draws a line, inherits the class Point as it has to deal...
read more Virtual keyword is used in inheritance to avoid ambiguity that may rise especially during multiple inheritance. Let me explain it with an example. Consider a class "Point" that reads and plots (x,y) co-ordinates. A new class "Line" that draws a line, inherits the class Point as it has to deal with starting and ending point. Similarly another class "Circle" also inherits class Point to plot the centre. Now if you want to create a class that draw a PieChart, It has to draw both lines and circle. So the easiest method is to inherit both the Line and Circle classes. On implementing this will lead to a simple problem that the class PieChart will inherit the base class Point two times (i) through Line Class (ii) through Circle class This obviously confuse the compiler that which copy it has to execute. This can be solved by adding a Virtual keyword while inheriting the first base class "Point" . This keyword prevents the creation of multiple copies for same class. So when you derive a class from two or more classes that are already subclasses of same class, ambiguity occurs due to the creation of multiple copies of base class. To avoid this "Virtual" Keyword is used. Virtual keyword is also used to create Virtual functions that enables Run-time Polymorphism. read less
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Tripti Pandey
Computer wizard and yoga medication
"virtual" keyword is used in case of multiple inheritance to remove ambiguity Here at level 1, when two or more class are derived from single base class by using virtual keyword,all derived class carry same features of base class which can be reused ; now when a class is derived in 2nd level , then...
read more "virtual" keyword is used in case of multiple inheritance to remove ambiguity Here at level 1, when two or more class are derived from single base class by using virtual keyword,all derived class carry same features of base class which can be reused ; now when a class is derived in 2nd level , then in this case above derived class i.e class in 1st level act as base class and "2nd level derived class have only single base object", irrespective of being derived from multiple class And this is how ambiguities are eliminated by virtual keyword ...... but incase virtual keyword are not used in 1st level classes then 2nd level derived class will contain more number of data sets/ base object depending on number of base class it have And this creates ambiguity ...... thus virtual key word eliminates ambiguity. For example: class A is base class, class B & C are virtually derived class in 1st level at last class D is derived from two classes B & C , still class D have one single base object . this is because of virtual keyword. read less
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Sridhar Achanta
B.E (Computer Science & Engineering) 78%; MS (Computer Science) (USA) (GPA: 3.8/4.0)
Virtual keyword can be used with classes as well as methods. When used with classes, it avoids ambiguity in inheritance. When it is used with methods, it allows method overriding and thus supports run-time polymorphism.
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Ravichandran M
Virtual keyword determines if a member function of a class can be over-ridden in its derived classes.
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Virtual is used when we want that the class functionality is override in each class it used. So that if anyone dont give the functionality of virtual class in child class it used the virtual class functionality or if he give the functionality it used that functionality. Ex. Camera in Mobile. We want...
read more Virtual is used when we want that the class functionality is override in each class it used. So that if anyone dont give the functionality of virtual class in child class it used the virtual class functionality or if he give the functionality it used that functionality. Ex. Camera in Mobile. We want that the Camera functionality is enhanced in every class. In that case we use virtual Keyword. read less
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Rajamohan Sangaramoorthy
I am a java developer and i have 10year experience in training of information technology
Virtual functions are member functions whose behavior can be overridden in derived classes. As opposed to non-virtual functions, the overridden behavior is preserved even if there is no compile-time information about the actual type of the class. If a derived class is handled using pointer or reference...
read more Virtual functions are member functions whose behavior can be overridden in derived classes. As opposed to non-virtual functions, the overridden behavior is preserved even if there is no compile-time information about the actual type of the class. If a derived class is handled using pointer or reference to the base class, a call to a overridden virtual function would invoke the behavior defined in the derived class. This behavior is suppressed if the function is selected using qualified name lookup (that is, if the function's name appears to the right of the scope resolution operator ::) read less
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when you use virtual then we can use other class function to another class whether that function not belong to it.
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Chetan Chauhan
Computer Classes
Virtual keyword is used to avoid ambiguity in inheritance. That is to resolve the ambiguity when there is/are member function with same prototype in multiple base classes.
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