Hello world program

Hello world is the name of a program that simply prints out "Hello world!".

This is a traditional first program to write when learning a new programming language, and can be a useful sanity test to make sure that a language's development environment and run-time environment are correctly installed.

While minimal test programs such as this existed since the development of programmable computers, the tradition of using "Hello world!" as the test message was probably started by its use as an example program in the book The C Programming Language, by Brian Kernighan and Dennis Ritchie.

Here are some examples in different languages:

• Ada

   with Ada.Text_Io; use Ada.Text_Io;
   procedure Hello is
   begin
      Put_Line ("Hello world!");
   end Hello;

• Assembly (x86 CPU, DOS, TASM syntax)

   MODEL SMALL
   IDEAL
   STACK 100H

   DATASEG
       HW      DB      'Hello, World!$'

   CODESEG
       MOV AX, @data
       MOV DS, AX
       MOV DX, OFFSET HW
       MOV AH, 09H
       INT 21H
       MOV AH, 4CH
       INT 21H
   END

• BASIC

   PRINT "Hello world!"

• Brainfuck

   >+++++++++[<++++++++>-]<.>+++++++[<++++>-]<+.+++++++..+++.[-]>++++++++[<++++>-]
   <.>+++++++++++[<++++++++>-]<-.- - - - - - - -.+++.- - - - - - . - - - - - - - -
   .[-]>++++++++[<++++>-]<+.[-]++++++++++.
   

• C

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

• C++

   #include <iostream>
   int main()
   {
       std::cout << "Hello world!" << std::endl;
       return 0;
   }

• COBOL

   IDENTIFICATION DIVISION.
   PROGRAM-ID.     HELLO-WORLD.

   ENVIRONMENT DIVISION.

   DATA DIVISION.

   PROCEDURE DIVISION.
   DISPLAY "Hello, World".
   STOP RUN.

• Common Lisp

   (format t "Hello world!~%")

• Forth

   ." Hello world!" 10 EMIT

• INTERCAL

  PLEASE DO ,1 <- #13
  DO ,1 SUB #1 <- #238
  DO ,1 SUB #2 <- #112
  DO ,1 SUB #3 <- #112
  DO ,1 SUB #4 <- #0
  DO ,1 SUB #5 <- #64
  DO ,1 SUB #6 <- #238
  DO ,1 SUB #7 <- #26
  DO ,1 SUB #8 <- #248
  DO ,1 SUB #9 <- #168
  DO ,1 SUB #10 <- #24
  DO ,1 SUB #11 <- #16
  DO ,1 SUB #12 <- #158
  DO ,1 SUB #13 <- #52
  PLEASE READ OUT ,1
  PLEASE GIVE UP

• Java

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

• Java GUI

   import java.awt.*;
   import java.awt.event.*;

   public class HelloFrame extends Frame {
     HelloFrame(String title) {
       super(title);
     }
     public void paint(Graphics g) {
       super.paint(g);
       java.awt.Insets ins = this.getInsets();
       g.drawString("Hello, World!", ins.left + 25, ins.top + 25);
     }
     public static void main(String args [])
     {
       HelloFrame fr = new HelloFrame("Hello");

       fr.addWindowListener(
         new WindowAdapter() {
           public void windowClosing(WindowEvent e)
           {
             System.exit( 0 );
           }
         }
       );
       fr.setResizable(true);
       fr.setSize(500, 100);
       fr.setVisible(true);
     }
   }

• Pascal

   program Hello;
   begin
       writeln('Hello world!');
   end.

• Perl

   print "Hello world!\n"

• PHP3

   <?php
       echo "Hello world!\n";
   ?>

• PL/I

   Test: procedure options(main);
      declare My_String char(20) varying initialize('Hello, world!');
      put skip list(My_String);
   end Test;

• Python

   print "Hello world!"

• Ruby (similarity to Perl version is not accidental)

   print "Hello world!\n"

• Smalltalk

   Transcript show: 'Hello world!'

• SQL

   SELECT 'Hello world!' FROM DUAL;

• Turing

   put "Hello world!"

Many more examples can be found at Hello, World Page!.

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/Talk