C# Class

A class is a blueprint of an object. An object in the real world will have properties like shape, color, weight etc. Likewise, in object-oriented programming, a class defines certain properties, events, and functionalities that an object can have.

Defining a class

In C#, a class is defined by using the class keyword. Following is the general structure of a class.

access_specifier class  class_name 
{
    //One or more Variables
    access_specifier data_type variables;
    //constructor
    access_specifier constructor(){}
    //one or more Methods
    access_specifier return_type method(parameters) {}   
}

• Access_specifier – Access specifiers are used to define the accessibility of the class and it’s member variables and methods. private, public, protected and internal are the access specifiers in C#. We’ll learn about them later.
• data_type – The datatype indicates the type of data stored in the variable.
• constructor – The constructor is a special member function of the class. It is called when an object is created.Constructor has the same name of the class.

Example

using System;   //Adding namespaces
namespace LearnCSharp   //Namespace of the class
{
    class MyClass
    {
        //Declaring Member variables
        public int length;
        public int height;
        public string name;
        public MyClass()    //Constructor
        {
            length = 12;
        }
        //A member method
        public void ShowData()
        {
            height = 20;
            Console.WriteLine(length);
            Console.WriteLine(height);
            Console.WriteLine(name);
            Console.ReadKey();
        }
    }
    class Program   //The class
    {
        static void Main(string[] args) //Main method
        {
            MyClass cl= new MyClass();  //Creating an object
            cl.name = "Rectangle";  //Setting value for a member variable of MyClass
            cl.ShowData();  //Calling the member function of MyClass
        }
    }
}

Output

12
20
Rectangle