Thursday, November 28, 2013

What is an Object in Object Oriented Programming?

Objects are usable instances of classes. Using the blue print analogy, a class is a blueprint and object is building made from that blue print. Classes describe the type of objects.
For example we have a class (say Bike)

class Bike {
       
    }

Then we create object of this class as

Bike myObject = new Bike();

Objects share two characteristic. They have state and behavior. An object stores its state in fields (variables) and exposes its behavior through methods.
Software objects are conceptually similar to real world objects. For example we have real world object Dog.
Dog has state name, color, breed, hungry and behavior barking, fetching, wagging tail etc.
We represent it in software world as

class Dog
    {
        string name;
        string color;
        string breed;
        string hungry;
        void Barking()
        {  
            // function definition
        }
        void Fetching()
        {
            // function definition
        }
        void Waggingtail()
        {
            // function definition
        }
    }

Dog objDog = new Dog();

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