The free subroutine frees a block of memory previously allocated by the malloc subroutine. Undefined results occur if the Pointer parameter is not a valid pointer. If the Pointer parameter is a null value, no action will occur. The realloc subroutine changes the size of the block of memory pointed to by the Pointer parameter to the number of bytes specified by the Size parameter and returns a new pointer to the block. The pointer specified by the Pointer parameter must have been created with the malloc, calloc, or realloc subroutines and not been deallocated with the free or realloc subroutines. Undefined results occur if the Pointer parameter is not a valid pointer.

Multiple inheritance is a feature in C++ by which one class can be of different types. Say class teaching Assistant is inherited from two classes say teacher and Student.

Early binding refers to the events that occur at compile time. Early binding occurs when all information needed to call a function is known at compile time. Examples of early binding include normal function calls, overloaded function calls, and overloaded operators. The advantage of early binding is efficiency.

Late binding refers to function calls that are not resolved until run time. Virtual functions are used to achieve late binding. When access is via a base pointer or reference, the virtual function actually called is determined by the type of object pointed to by the pointer.

The C++ language provides a single global namespace.Namespaces allow to group entities like classes, objects and functions under a name.

The function declaration should be preceded by the keyword friend.The function definitions does not use either the keyword or the scope operator :: The functions that are declared with the keyword friend as friend function.Thus, a friend function is an ordinary function or a member of another class.

Dynamic binding (also known as late binding) means that the code associated with a given procedure call is not known until the time of the call at run time.It is associated with polymorphism and inheritance.

A default constructor is a constructor that either has no parameters, or if it has parameters, all the parameters have default values.