An object is the basic key concept of Object Oriented Programming. As mentioned before it can be anything around us – a person, place, any activity or any other identifiable entity. Every object is characterised by:
Identity: This is the name that identifies an object. For example a Student is the name given to anybody who is pursuing a course. Or an i-phone is a mobile phone that has been launched by Apple Inc.
Properties: These are the features or attributes of the object. For example a student will have his name age, class, date of birth etc. as his attributes or properties. A mobile phone has model, color, price as its
Behaviour: The behaviour of an object signifies what all functions an object can perform. For example a student can pass or fail the examination. A mobile phone can click and store photographs (behave like a camera).
So an object clearly defines an entity in terms of its properties and behaviour. Consider an example of an object – Windows mobile phone. This phone has certain properties and certain functions which are different from any other mobile phone- say an Android phone. Both are mobile phones and so possess common features that every mobile phone should have but yet they have their own properties and behaviours. The data of a particular object can be accessed by functions associated with that object only. The functions of one object cannot access the data of another object.