Structure

Structure – It is also a user define similar to a class that can contain variables methods as well as constructor in it.

Differences between classes and structure – (v. imp)

CLASS	STRUCTURE
1.  It reference type.	1.  it is a value type
2.  Memory allocation is done on managed heap, so gets the support of garbage collector follow Automatic memory management.	2.  Memory allocation is done on stack which doesn’t have support of garbage collector for memory management, but faster in access.
3.  Using new operator to create the object of class (reference type) is mandatory.	3.  Using new operator to create the object of structure (value type) is only optional.
4.  Can contain variable declaration as well as initialization.	4.  Can contain variable declaration but cannot be initialized.
5.  variable of the class can be initialized in three ways i.e. – - at the time of declaration or - under the constructor  or - using the object.	5.  variable of the Structure can be initialized only in  two ways i.e. – - under the constructor  or - using the object.
6.  A class require a constructor for creating the object of it , which need not be a default constructor	6.  A structure also requires a constructor for creating its object without using new operator and in this case it use default constructor only. So default constructor is mandatory for structure and will be defined implicitly, that cannot be defined by programmer explicitly...
7.  If defined with Zero constructor after compilation there will be one constructor and if defined with ‘n’ constructors after compilation there will be ‘n’ constructors only	7.  If define with Zero constructor after compilation there will be One constructor and define with ‘n’ after compilation there will be ‘n+1’ constructor , because there is implicit default constructor always
8.  It supports both Implementation and Interface inheritance.	8.  It supports only Interface Inheritance.

Note – All the predefine type which comes under the value type category are implemented as structure under namespace.

Eg – int32, single, Boolean etc,

Whereas all predefined data types which comes under refinance type category are implemented as Classes

Eg – string and object.

- Add a code file naming it as MyStruct.cs and write the following 

using System; namespace oopsProject {     struct MyStruct     {         int x;         public MyStruct(int x)         {             this.x = x;         }         public void Display()         {             Console.WriteLine(" Method under struct :" + x);         }         static void Main()         {             MyStruct obj1; // using default constructor             obj1.x = 50; obj1.Display();             MyStruct obj2 = new MyStruct(150);             obj2.Display();             Console.ReadLine();         }     } }

Add one more code file naming it as MyStruct2.cs and write the following:

using System; namespace oopsProject {     struct MyStruct2     {         static void Main()         {             MyStruct obj = new MyStruct(300);             obj.Display();             Console.ReadLine();         }     } }