Structs in C#

This article is for beginners. In this article we will cover :-

• What is struct? How to define struct.
• What is the use of "new" operator in struct.
• Demo code with proof of concept (poc).

Introduction
Structs are similar as class. These are the value types which means they will store in the stack. It can be declare by keyword struct.

• A struct is always derived from System.ValueType, which in turn derives from System.Object.
• We are not permitted to define a constructor that takes zero argument inside a struct whereas we can define a parameterized constructor.
• The new operator work differently in struct. Instead of allocating memory on the heap, the new operator simply calls the appropriate constructor, according to the parameters passed to it.
• In struct we cannot initialize instance member variable. It will give compilation error.
• Struct do not support inheritance.

 Demo
namespace StructDemo

{

  public struct Employee

  {

    private int _age;

 

   //public int age=5; // can't initialize instance variable it will give compilation error as: cannot have instance field initializers in structs

 

   //public Employee() { } //can't define default constructor, compilation error occurs as: Structs cannot contain explicit parameterless constructors

   

  public Employee(int age)

  {

   _age = age;

  }

  public int Age

  {

   set { _age = value; }

   get { return _age; }

  }

  public void display()

  {

   Console.WriteLine("Age::" + _age);

  }

 }

 

 class Program

 {

  static void Main(string[] args)

  {

    //creating employee object with default constructor   

   Employee e1 = new Employee();

   e1.Age = 20;

   Console.WriteLine("calling default constructor..");

   e1.display();

     

   //To call parameterized constructor use "new" operator.   
   Employee e2 = new Employee(25);

   Console.WriteLine("calling parameterized constructor..");

   e2.display();

   Console.ReadLine();

  }

 }

}

 

 Output