constructor

■ Constructor

• A constructor is a special method that is used to initialize objects.  

• it is called when an object of a class is created. 

• It is used to set initial values for fields(variables)

• without constructor we can't create instance of a class (if we don't create a constructor explicity then compiler create the default constructor implicitly ) 

• the constructor name must match the class name, and it cannot have a return type (like void or int).

• All classes have constructors by default if you do not create a class constructor yourself, C# creates one for you.

• A static constructor cannot be a parameterized constructor because it get called automatically by the runtime.

➤ Types of Constructor

1) Default Constructor

2) Parameterized Constructor

3) Copy Constructor

4) Static Constructor

1) Default Constructor or parameter-less constructor

• A constructor with no parameters is called a default constructor. 

• The default constructor initializes all numeric fields to zero and all string and object fields to null, unless explicitly initialized to different values in the constructor.

2) parameterised constructor

• A constructor having at least one parameter is called as parameterized constructor. 

It can initialize each instance of the class to different values.

3) Copy constructor

• This constructor creates an object by copying variables from another object. 

• Its main use is to initialize a new instance to the values of an existing instance.

• It takes class name as parameter. 

4) Static Constructor

• if we use static keyword before the name of constructor then it is called static constructor. 

• If there are static fields in our class then compiler will provide implicit static constructor until we create explicit constructor. 

• It is called automatically by the runtime before any static members are accessed or any static methods are called, and it runs only once for the class.

• A static constructor is used to initialize static fields of the class and to be executed only once.

• static constructors cannot have parameters and cannot be called directly.

• static constructors cannot be overloaded. 

• We can't use any modifier with static constructor 

    Example  :-

public class MyClass

{

    public static int Count;

    

    // Static constructor

    static MyClass()

    {

        // Initialize static members

        Count = 0;

        Console.WriteLine("Static constructor called.");

    }

    public static void IncrementCount()

    {

        Count++;

    }

}

// Usage

MyClass.IncrementCount();

Console.WriteLine(MyClass.Count); // Output: 1