OBJECTS
Objects are the basic run-time entities in an object-oriented system. They may represent a person, a
place, a bank account, a table of data or any item that the program must handle.
The fundamental idea behind object oriented approach is to combine both data and function
into a single unit and these units are called objects.
The term objects means a combination of data and program that represent some real word
entity. For example: consider an example named Amit; Amit is 25 years old and his salary is 2500.
The Amit may be represented in a computer program as an object. The data part of the object would
be (name: Amit, age: 25, salary: 2500)
The program part of the object may be collection of programs (retrive of data, change age,
change of salary). In general even any user –defined type-such as employee may be used. In the
Amit object the name, age and salary are called attributes of the object.
CLASS
A group of objects that share common properties for data part and some program part are
collectively called as class.
In C ++ a class is a new data type that contains member variables and member functions that
operate on the variables.
DATA ABSTRACTION :
Abstraction refers to the act of representing essential features without including the back
ground details or explanations. Classes use the concept of abstraction and are defined as size, width
and cost and functions to operate on the attributes.
DATA ENCAPSALATION
The wrapping up of data and function into a single unit (called class) is known as
encapsulation. The data is not accessible to the outside world and only those functions which are
wrapped in the class can access it. These functions provide the interface between the objects data and
the program.
