Table of Contents
Can objects of abstract classes be created?
No, we can’t create an object of an abstract class. The reference variable is used to refer to the objects of derived classes (subclasses of abstract class). An abstract class means hiding the implementation and showing the function definition to the user is known as Abstract class.
Can an abstract class have data members?
An abstract class can have a data member, abstract method, method body (non-abstract method), constructor, and even main() method.
Is it legal to have an abstract class with all member functions pure virtual?
Pure Virtual definitions Pure Virtual functions can be given a small definition in the Abstract class, which you want all the derived classes to have. Still you cannot create object of Abstract class. Inline pure virtual definition is Illegal.
Why we can not create an object of abstract class or interface?
Because an abstract class is an incomplete class (incomplete in the sense it contains abstract methods without body and output) we cannot create an instance or object; the same way you say for an interface.
Can abstract class have static data members how Why?
1) Yes. An abstract class can have a static variable.
How many objects can be created from an abstract class?
Q. | How many objects can be created from an abstract class? |
---|---|
B. | One |
C. | Two |
D. | As many as we want |
Answer» a. Zero |
Why abstract classes Cannot have any objects?
you can’t create a object of abstract class because there is an abstract method which has nothing so you can call that abstract method too. If we will create an object of the abstract class and calls the method having no body(as the method is pure virtual) it will give an error.
What happens if the derived class from an abstract class does not provide implementation of pure virtual function?
3) If we do not override the pure virtual function in derived class, then derived class also becomes abstract class. The following example demonstrates the same.
Can data member be virtual?
It is not used to identify that the base class pointer is pointing to derived class. Only non static member functions can be virtual. Data members can not be.
Is it possible to create an object of abstract class?
Still you cannot create object of Abstract class. Also, the Pure Virtual function must be defined outside the class definition. If you will define it inside the class definition, complier will give an error. Inline pure virtual definition is Illegal.
What is the difference between abstract class and pure virtual class?
Classes inheriting an Abstract Class must provide definition to the pure virtual function, otherwise they will also become abstract class. Abstract class cannot be instantiated, but pointers and refrences of Abstract class type can be created. Abstract class can have normal functions and variables along with a pure virtual function.
What is abstract class in C++?
Abstract Class and Pure Virtual Function in C++ Abstract Class is a class which contains atleast one Pure Virtual function in it. Abstract classes are used to provide an Interface for its sub classes. Classes inheriting an Abstract Class must provide definition to the pure virtual function, otherwise they will also become abstract class.
Can abstract class be instantiated in Java?
Abstract class cannot be instantiated, but pointers and references of Abstract class type can be created. Abstract classes are mainly used for Upcasting, so that its derived classes can use its interface. If an Abstract Class has derived class, they must implement all pure virtual functions, or else they will become Abstract too.