Constructors in DART language

In this article, I am going to explain about constructors in dart language.
  • 3477

Constructors in Dart

A  constructor is a class member function in dart language   that has same name class itself. Constructors does not inherited by  sub class.

Example of constructor

class Construct{

  Construct.MyConstruct(){

    print("Wecome in Dart Constructor !");

  }

  Construct.MyConstruct1(String s){

    print("Wecome in Parametrized Constructor !");

  }

}

void main()

{

  Construct obj = new Construct.MyConstruct();

  Construct obj1 = new Construct.MyConstruct1("Dart");
}

Output:

cons.png

Constructor are different types

  • Default constructor

    The default constructor is also know as no argument constructor, if you do not declare a default constructor, it is automatically created.

Example of default constructor

class DefaulConstruct{

  DefaulConstruct() {

  print("I am a Default Constructor");}

}

void main() {

  DefaulConstruct obj = new DefaulConstruct();
}


Output:

defaultconst.png

  • Named constructor

    You can used named constructor to implement multiple constructor for a class.
     

  • Factory constructor

    factory constructor is used, when we want to create a instance only once; and use this instance for multiple time.

  • Constant constructor

    An immutable compile time constant object is known as a const object; and constant constructor is used for it.

Example of constant constructor
 

class constcon{

  final int a;

  const constcon(this.a);

}

main(){

  var a = const constcon(1);

  var b= const constcon(1);

  print("The value of with const constructor is ${a==b}");

   /********And if you check without const **************/

   var c = new constcon(1);

   var d = new constcon(2);

   print("The value of WithOut const constructor is ${c==d}");
}


Output:


 constconstr.png

Ask Your Question 

Got a programming related question? You may want to post your question here
 
© 2019 DotNetHeaven. All rights reserved.