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:

• 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;
    }

• 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 2 using swing:

 // builds a Java window and prints "Hello, world" using Swing JFrame components...

 import java.awt.*;
 import javax.swing.*;
 import java.awt.event.*;

public class xapp extends JFrame

 {
	jpanel j;

	public xapp()
	{

	super ("Hello World Application");

	Container contentPane = getContentPane();
	j = new jpanel();
	contentPane.add(j);
	}

	public static void main(String args[])
	{
		final JFrame f = new xapp();
		f.setBounds(100, 100, 300, 300);
		f.setVisible(true);	
		f.setDefaultCloseOperation(EXIT_ON_CLOSE); //tidy up...
	}
 }

class jpanel extends JPanel

 {
	jpanel()
	{
	setBackground(Color.white);
	}

	public void paintComponent(Graphics g)
	{
	super.paintComponent(g);
	g.drawString("Hello world!",0, 65);
	}

 }

• 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!"

• 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