OOPS

Object

Object is a real world entity.

• Struct in C ?

• Data Type ?

Defines the type of data.

• User defined e.g. Employee, Student etc.
• Language defined e.g. int, char, float, String etc.

User Defined Data-Types

Basic example:

C

struct Employee {
  char name[200];
  int age;
  float salary;
}

struct Employee employee

C++

class Employee {
  string name;
  int age;
  float salary;
};

Object & Instances

“Names given to object are instances.”

References & Pointers

Types of memory:

• Static
• Heap
• Stack

Characterstics of an object

• Abstraction
• Encapsulation
• Inheritance
• Polymorphism

Abstraction

• Reduces complexity.
• Provides easeness.

Abstraction allows to layer the semantics of a complex system into more manageable pieces.

• Improves extensiblity.
• Use of modules.

It is achieved using the abstract keyword in Java or virtual functions / pure-virtual-functions in C++.