Class in Dart Programming

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Jun 6, 2024

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Classes are user-defined data types that describe the behavior and characteristics of an entity. An entity can be any real-world object. For example, books, automobiles, persons, and so on can be thought of as entities. Hence, each of these can be represented using classes.

A class comprises data members and member functions. The keyword class is used in Dart for creating a class. The definition of a class starts with the class keyword, class name, and the body of the class which is enclosed by the curly braces.

The syntax of a class definition is as follows:

Objects:

When an instance of a class is created, it is called an Object. In Dart, multiple objects of a class can be created and used.

It is recommended to use meaningful names for classes and objects. For example, Employee can be a class name, and emp1 and emp2 can be objects.

The syntax for creating objects is as follows:

Note: Although many programming languages support the use of new keywords to create objects, in Dart, it is optional and can be omitted.

Instance and Class Variables

Variables related to classes can be categorized into instance variables and class variables.

Instance Variable:

• Instance Variable is basically, a class variable shared by all class instances.
• It can have different values for each object.
• The value is retained as long as the object is active.
• Example: class NewClass { int Counter; }
  
  

Class Variable:

• A class Variable is a static variable declared inside a class.
• It can have only one value and is shared among all objects.
• The value is retained until the program terminates.
• Example: class NewClass{ static int counter; }