C++ Questions

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.

A heap is a way to organize the elements of a range that allows for fast retrieval of the element.

A class is said to be a container class which is utilized for the purpose of holding objects in memory or persistent media. A generic class plays a role of generic holder. A container class is a good blend of predefined behavior and an interface that is well known. The purpose of container class is to hide the topology for the purpose of objects list maintenance in memory. A container class is known as heterogeneous container, when it contains a set of different objects. A container class is known as homogeneous container when it contains a set of similar objects.

If an error occurs in program, then only exception object is created otherwise, It will not be created. So it’s expensive to use in the program.

Class can have a public method for specific data type conversions.
for example:
class B
{
double value;
public  B(int i )
operator double()
{
return value;
}
};
B BObject;
double i = BObject; // assigning object to variable i of type double.
now conversion operator gets called to assign the value.

Allocaters are implemented in C++ standard library but it is used for C++ template library.

- Friend classes are useful when a class wants to hide features from users which are needed only by another, tightly coupled class. 

- Implementation details can be kept safe by providing friend status to a tightly cohesive class.