If we invoked the interface as public means, We can access the program from other programs also.

There are three types of classes. They are abstract base classes, concrete derived classes, standalone classes.

Overriding refers to a derived class function that has the same name
and signature as a base class virtual function.

Class hierarchies promote reuse in two ways. They are code sharing and interface sharing.

Separation of interface from implementation

A class that expresses functionality rather than its primary design role is called a mixin.

cerr is an object of class ostream that represents the standard error stream. It is associated with the cstdio stream stderr.

clog is an object of class ostream that represents the standard logging stream. It is associated with the cstdio stream stderr, like cerr.

We can make user-defined types with streams by overloading the insertion operator () to read objects from streams.

There are three types of guarantees in c++. They are weak, strong and no-throw.