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Virtual functions are used to suport runtime polymorphism.In C++,if we have inheritance and we have overridden functions in the inherited classes,we can declare a base class pointer and make it to point to the objects of derived classes.When we give a keyword virtual to the base class functions,the compiler will no do static binding,so during runtime ,the base class pointer can be used to call the functions of the derived classes.Thus virtual functions support dynamic polymorphism.
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Why run time polymorphism is dynamic and compile time polymorphism is static?
The simple answer is that compile-time polymorphism occurs at compile time while runtime polymorphism occurs at runtime. The actual answer is that compile-time polymorphism results in the compiler generating source code on your behalf while runtime polymorphism relies on function pointers or virtual methods to determine the next instruction at runtime. Compile-time polymorphism therefore applies to template functions and classes since that is the only way the compiler can generate source code on your behalf. To achieve this, the runtime type for the template parameters must be fully-defined at compile time, even if those types have runtime polymorphic characteristics of their own. Runtime polymorphism applies to virtual methods and function pointers, both of which can be used to dynamically alter the execution path of your program. Virtual methods are made possible through virtual tables, which are essentially just arrays of function pointers. Each runtime type that derives from a base class with virtual methods provides its own virtual table, thus the runtime type determines which specific function overrides will be invoked at runtime, even if the runtime type cannot be determined at compile time. In this way you can generalise your code to work with the base type but still get the expected polymorphic behaviour whenever a derived type is passed instead.
How does java achieve run time polymorphism?
Polymorphism is Greek for "many forms". There are two types of polymorphism: static and dynamic. Static polymorphism occurs at compile time and is also known as compile time polymorphism. Dynamic polymorphism occurs at runtime and is also known as runtime polymorphism. Runtime polymorphism is a primary feature of the object-oriented programming paradigm. We achieve runtime polymorphic behaviour by defining virtual methods in a base class which derived classes can then override in order to provide more specialised implementations. Whenever we invoke one of these methods, the most-specialised override is executed automatically. In other words, polymorphic objects will behave according to their runtime type even when the runtime type cannot be determined at compile time.
What is the Practical application of a derived class object stored in base class pointer?
If you have base class derived object pointing by base class pointer, then you have the power of run time polymorphism in your hand, which gives you the ability to call the derived class implementation of the virtual member function. If we declare the member function as virtual in base class which needs to overridden in derived class, then you can decide at run time which implementation will be called at run time.
What is compile time polymorphism in java?
Compile Time Polymorphism in Java is when you have the several methods with same name and different parameters and compiler has to decide how to select which method has to run based on the arguments hence the name Compile time polymorphism or method overloading.
What is Difference between dynamic polymorphism and static polymorphism with example?
Static polymorphism is used the concept of early binding or we can say compile time binding where as dynamic polymorphism used the concept of late binding or run time binding.
Why run time polymorphism is dynamic and compile time polymorphism is static?
The simple answer is that compile-time polymorphism occurs at compile time while runtime polymorphism occurs at runtime. The actual answer is that compile-time polymorphism results in the compiler generating source code on your behalf while runtime polymorphism relies on function pointers or virtual methods to determine the next instruction at runtime. Compile-time polymorphism therefore applies to template functions and classes since that is the only way the compiler can generate source code on your behalf. To achieve this, the runtime type for the template parameters must be fully-defined at compile time, even if those types have runtime polymorphic characteristics of their own. Runtime polymorphism applies to virtual methods and function pointers, both of which can be used to dynamically alter the execution path of your program. Virtual methods are made possible through virtual tables, which are essentially just arrays of function pointers. Each runtime type that derives from a base class with virtual methods provides its own virtual table, thus the runtime type determines which specific function overrides will be invoked at runtime, even if the runtime type cannot be determined at compile time. In this way you can generalise your code to work with the base type but still get the expected polymorphic behaviour whenever a derived type is passed instead.
How is run time polymorphism accomplished?
Through inheritance and virtual functions.
How does java achieve run time polymorphism?
Polymorphism is Greek for "many forms". There are two types of polymorphism: static and dynamic. Static polymorphism occurs at compile time and is also known as compile time polymorphism. Dynamic polymorphism occurs at runtime and is also known as runtime polymorphism. Runtime polymorphism is a primary feature of the object-oriented programming paradigm. We achieve runtime polymorphic behaviour by defining virtual methods in a base class which derived classes can then override in order to provide more specialised implementations. Whenever we invoke one of these methods, the most-specialised override is executed automatically. In other words, polymorphic objects will behave according to their runtime type even when the runtime type cannot be determined at compile time.
What is polymorphism and its types?
Polymorphism means multiple form of a function, variable or object. In Computer Science, polymorphism is a programming language feature that allows values of different data types to be handles using a common interface. There are three types : Ad-Hoc Polymosphism, Parametric Polymorphism, Subtype/Inclusion Polymorphism. Source: Wikipedia.
What is the Practical application of a derived class object stored in base class pointer?
If you have base class derived object pointing by base class pointer, then you have the power of run time polymorphism in your hand, which gives you the ability to call the derived class implementation of the virtual member function. If we declare the member function as virtual in base class which needs to overridden in derived class, then you can decide at run time which implementation will be called at run time.
What is compile time polymorphism in java?
Compile Time Polymorphism in Java is when you have the several methods with same name and different parameters and compiler has to decide how to select which method has to run based on the arguments hence the name Compile time polymorphism or method overloading.
What is Difference between dynamic polymorphism and static polymorphism with example?
Static polymorphism is used the concept of early binding or we can say compile time binding where as dynamic polymorphism used the concept of late binding or run time binding.
Define compile time polymorphism with short examples?
compiler can decide which form of the object should be invoked during compile time.this type of polymorphism is know as compile time polymorphism
What is the difference between compile time and run time polymorphism?
Runtime prolymorphism means overriding compiletile polymorphism means overloading
Can you have inline virtual functions in a class?
No, inlining is done at compile time whereas virtual functions are resolved at run time(late binding). So, virtual functions can't be inlined. Both properties are orthogonal.Inlining is a mere suggestion the compiler may ignore it if it is declared with virtual function.
What is virtual function in c plus plus?
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
Where to use polymorphism?
Polymorphism is used whenever you wish to achieve specific behaviour from a generic object, where the object's actual type may not be known or would be impossible to determine at compile time. By declaring virtual methods in the generic type (the base class), and overriding them in the derived type, you ensure that the derived object does "the right thing" regardless of its actual type, and regardless of whether the method is called directly or indirectly via the base class. With polymorphism, there is no need to determine the actual runtime type of the object, you get that for free simply by calling the appropriate virtual methods.
