The Object Oriented Approach
The fundamental idea behind the object-oriented languages is to combine into a single unit both data and the functions that operate on that data. Such a unit is called an object.
An object's functions, called member functions in C++, typically provide the only way to access its data. If you want to read a data item in an object, you call a member function in an object. It will read the item and return the value to you. You cant access the data directly. The data is hidden, so it is safe for accidental alteration. Data and its functions are said to be encapsulated into a single entity. Data encapsulation and data hiding are the key terms in the description of object-oriented languages. A C++ program typically consists of a number of objects, which communicate with each other by calling one another's member functions.