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Classes and Objects In C#

Class  is a collection of fields, properties and methods. It depicts real life entities and is a fundamental concept in Object Oriented Programming.
 A class is a user-defined blueprint  from which objects are created . A class is a user defined data type of reference type.

Lets take a example of a Car . It has different attributes like color,maximum speed,no of gears on with a built in audio player  and so on.

public class Car
{
    private string  _color; //a variable and a field with data type string
    // a variable and  a property  
    public string Color  
    {
        get
        {
            return _color;
        }
        set
        {
            _color= value;
        }
public void  PlayAudio()
{
//implementation logic
}
}

Declaration Of Class: 
<access specifier><keyword:class> <class name: Car>
public class car

if access identifier is not explicitly mentioned a class has internal access identifier as default while methods and properties have private access identifier.

Fields :  field is private to the class and stores the actual data.

Properties : Properties are exposed contract which uses the underlying fields.
                  Properties are also called accessors as they offer a way to get and set a field in the class.
                  Properties can be read-only,write-only or both by declaring get{},set{} or both.

Object :
Object is an instance of a class which is created at run time. It is a memory  allocation according to the class of which it is an instance of  . It is used to access properties and methods in a class.

 Initializing an object
An object is initialized by using the keyword new.

Car c=new Car();
 here c is an object of type car.
if we split the above initialization in two lines
Car c ; // it is a declaration which states that c is a variable of type class c;
c=new Car();// now c is an object of class Car

and we can access the properties and methods of the class
c.Color=red;  //assigning value to the property of the object
string color=c.Color; //getting the value of the property from the object
c.PlayAudio(); //invoking method





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