What is constructor How to use constructor

what is constructor  

Constructor is a special type of method which name is same as class name .when we create a object of  class then the method called automatically.
The following example of constructor-
using System;
using System.Collection. Generic;
using System.Text;
namespace keshav
{
               class Ravi
               {
                 public Ravi()
                  {
                         Console.WriteLine("Always work hard ");
                  }
                  public static void Main(string[]args)
                   {
                         Ravi rs=new Ravi();

                   }

               }
}