Page 9 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes 1.1 Basic Concept of Object-oriented Programming

Procedural programming deals with functional parts of the problem. Programmers identify
what actions must be taken to solve the problem at hand. Let us now, try to understand what
aspect of problems is dealt with in object-oriented approach. We shall be discussing some
essential concepts that make a programming approach object-oriented.
In object-oriented parlance, a problem is viewed in terms of the following concepts:
1. Objects
2. Classes
3. Data abstraction

4. Data encapsulation
5. Inheritance
6. Polymorphism

7. Dynamic binding
8. Message passing
Let us now study the entire concept in detail.
1. 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; they may also represent user-
defined data such as vectors, time and lists.

They occupy space in memory that keeps its state and is operated on by the defined
operations on the object. Each object contains data and code to manipulate the data.

Notes Objects can interact without having to know details of each other data or code.
The figure 1.1 shows the two notations popularly used.

Figure 1.1

Object: STUDENT
STUDENTS
DATA
Total
Name
Date-of-birth
Marks
..............
..............
Avg
FUNCTIONS
Total
Avg.
Display
Display
(a)

(b)

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