What is the definition of abstract class and virtual function?

A class which have abstract methods with no implementations.You can’t create object for this class.
virtual function:
If u override a member function in base class and derive class or if u want to achieve the runtime polymorphisms then we have to declare base class function as virtual function.This function called by base class pointer.

What is encapsulation?

Containing and hiding information about an object, such as internal data structures and code. Encapsulation isolates the internal complexity of an object’s operation from the rest of the application. For example, client component asking for net revenue from a business object need not know the data’s origin.

What is function overloading and operator overloading?

Function overloading: C++ enables several functions of the same name to be defined, as long as these functions have different sets of parameters (at least as far as their types are concerned). This capability is called function overloading. When an overloaded function is called, the C++ compiler selects the proper function by examining the number, types and order of the arguments in the call. Function overloading is commonly used to create several functions of the same name that perform similar tasks but on different data types.
Operator overloading allows existing C++ operators to be redefined so that they work on objects of user-defined classes. Overloaded operators are syntactic sugar for equivalent function calls. They form a pleasant facade that doesn’t add anything fundamental to the language (but they can improve understandability and reduce maintenance costs).

What is Overriding?

To override a method, a subclass of the class that originally declared the method must declare
a method with the same name, return type (or a subclass of that return type), and same parameter
The definition of the method overriding is:
· Must have same method name.
· Must have same data type.
· Must have same argument list.
Overriding a method means that replacing a method functionality in child class. To imply
overriding functionality we need parent and child classes. In the child class you define the same
method signature as one defined in the parent class.

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