print("Hello World!")

#include<stdio.h>
void main()
{
    printf("Hello World!");
    return 0;
}

#include<iostream>
using namespace std;
int main()
{
    cout<<"Hello World!";
    return 0;
}

#!usr/bin/sh 
echo "Hello World!";

puts "Hello World";

<?php
    echo "Hello World!";
?>

#!usr/bin/perl
print("Hello World!");

;以下代码来源于百度百科
DATA   SEGMENT                            
PRINT  DB "Hello World!", 0AH, 0DH, '$'  
DATA   ENDS                  
  
STACK  SEGMENT   STACK           
       DW  20  DUP(0)                       
STACK  ENDS                  
  
ASSUME CS:CODE, DS:DATA, SS:STACK            
  
CODE   SEGMENT                               
START:                                       
        MOV AX, DATA                         
        MOV DS, AX                           
        MOV DX, OFFSET  PRINT                
        MOV AH, 09H
        INT 21H                              
        MOV AH, 4CH                          
        INT 21H
CODE   ENDS                                  
END    START