Functions in C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    public class Program
    { //if U write without 'public' then write it like
       //'void fun()','void fun3()' and 'void fun2',it is Ur choice.
         public void fun() //'fun' is function name.
        {
            Console.WriteLine("This is First Function");
        }
         public void fun3() //'fun3' is function name.
         {
             Console.WriteLine("This is 3rd Function");
         }
         public void fun2() //'fun2' is function name.
         {
             Console.WriteLine("This is 2nd Function");
         }
        static void Main(string[] args)
        { //'fun ,fun2 ,fun3 and p' is not key word U write any thing.
            Program p = new Program(); //using 'p' as a
                     //object of class 'Program' for calling.
            p.fun(); //with the help of 'p' calling 'fun' function.
            p.fun2(); //with the help of 'p' calling 'fun2' function.
            p.fun3(); //with the help of 'p' calling 'fun3' function.
            Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication
{
    public class Program
    {
        static void Main(string[] args)
        { //'fun ,fun2 ,fun3 and p' is not key word U write any thing.
            Program p = new Program(); //I using 'p' as a
            //object of class 'Program' for calling.
            p.fun(); //with the help of 'p' calling 'fun' function.
            p.fun2(); //with the help of 'p' calling 'fun2' function.
            p.fun3(); //with the help of 'p' calling 'fun3' function.
            Console.ReadKey();
        }
        //if U write without 'public' then write it like
        //'void fun()','void fun3()' and 'void fun2',it is Ur choice.
        public void fun() //'fun' is function name.
        {
            Console.WriteLine("This is First Function");
        }
        public void fun3() //'fun3' is function name.
        {
            Console.WriteLine("This is 3rd Function");
        }
        public void fun2() //'fun2' is function name.
        {
            Console.WriteLine("This is 2nd Function");
        }
	}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication
{
    public class Program
    { //1st calling 'fun', second 'fun2' and 3rd 'fun3' function.
         public void fun()
        {
            Console.WriteLine("This is First Function");
            fun2(); //I calling 'fun2' function here.
         }
         public void fun3()
         {
             Console.WriteLine("This is 3rd Function");
         }
         public void fun2()
         {
             Console.WriteLine("This is 2nd Function");
             fun3(); //I calling 'fun3' function here.
         }
        static void Main(string[] args)
        {
            Program p = new Program();
            p.fun(); //I calling 'fun' function.
            Console.ReadKey();
        }
    }
}