Displaying Message in different programming languages

#include<stdio.h>
void main()
{
printf("Hello World");
}

#include<iostream.h>
void main()
{
cout <<"Hello World";
}

class Main{
public static void main(String [] args)
{
System.out.println("Hello World");
}
}

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World");
        }
    }
}

<?php echo ('Hello World');?>