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Hello world program
A "hello world" program is a computer 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 compiler, development environment[?], and run-time environment are correctly installed.
Although this is a trivial exercise in a system where all of these are pre-configured, configuring a complete programming tool chain from scratch to the point where even trivial programs can be compiled and run may involve substantial amounts of work. For this reason, a simple program is used first when testing a new tool chain.
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:
|
Console
with Ada.Text_Io; use Ada.Text_Io;
procedure Hello is
begin
Put_Line ("Hello, world!");
end Hello;
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 AX, 4C00H
INT 21H
END
BEGIN { print "Hello, world!" }
Traditional - Unstructured BASIC
10 PRINT "Hello, world!"
20 END
More modern versions - Structured BASIC
print "Hello, world!"
GET "LIBHDR"
LET START () BE
$(
WRITES ("Hello, world!*N")
$)
"!dlrow olleH">v
,
^_@
++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<
+++++++++++++++.>.+++.------.--------.>+.>.
#include <stdio.h>
int main(void) {
printf("Hello, world!\n");
return 0;
}
#include <iostream>
using namespace std;
int main() {
cout << "Hello, world!" << endl;
return 0;
}
class HelloWorldApp {
public static void Main() {
System.Console.WriteLine("Hello, world!");
}
}
IDENTIFICATION DIVISION.
PROGRAM-ID. HELLO-WORLD.
ENVIRONMENT DIVISION.
DATA DIVISION.
PROCEDURE DIVISION.
DISPLAY "Hello, world!".
STOP RUN.
(format t "Hello world!~%")
- DOS batch
@echo off
echo "Hello, world!"
class HELLO_WORLD
creation
make
feature
make is
local
io:BASIC_IO
do
!!io
io.put_string("%N Hello, world!")
end -- make
end -- class HELLO_WORLD
-module(hello).
-export([hello_world/0]).
hello_world() -> io:fwrite("Hello, World!\n").
." Hello, world!" CR
WRITE(*,10)
10 FORMAT('Hello, World!')
STOP
END
H
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
public class Hello {
public static void main(String[] args) {
System.out.println("Hello, world!");
}
}
print "Hello, world!"
TERM EQU 19 the MIX console device number
ORIG 1000 start address
START OUT MSG(TERM) output data at address MSG
HLT halt execution
MSG ALF "MIXAL"
ALF " HELL"
ALF "O WOR"
ALF "LD "
END START end of the program
let main () =
print_endline "Hello world!";;
program Hello;
begin
writeln('Hello, world!');
end.
#!/usr/local/bin/perl
print "Hello, world!\n";
<?php
print("Hello, world!");
?>
#!/usr/local/bin/pike
int main() {
write("Hello, world!\n");
return 0;
}
Test: procedure options(main);
declare My_String char(20) varying initialize('Hello, world!');
put skip list(My_String);
end Test;
#!/usr/local/bin/python
print "Hello, world!"
say "Hello, world!"
#!/usr/bin/ruby
print "Hello, world!\n"
(display "Hello, world!")
(newline)
- sed (requires at least one line of input)
sed -ne '1s/.*/Hello, world!/p'
Transcript show: 'Hello, world!'
OUTPUT = "Hello, world!"
END
create table MESSAGE (TEXT char(15));
insert into MESSAGE (TEXT) values ('Hello, world!');
select TEXT from MESSAGE;
drop table MESSAGE;
#!/usr/local/bin/tcl
puts "Hello, world!"
put "Hello, world!"
#!/bin/sh
echo 'Hello, world!'
Graphical User Interfaces
MsgBox "Hello, world!"
#include <iostream>
#include <gtkmm/main.h>
#include <gtkmm/button.h>
#include <gtkmm/window.h>
using namespace std;
class HelloWorld : public Gtk::Window {
public:
HelloWorld();
virtual ~HelloWorld();
protected:
Gtk::Button m_button;
virtual void on_button_clicked();
};
HelloWorld::HelloWorld()
: m_button("Hello, world!") {
set_border_width(10);
m_button.signal_clicked().connect(SigC::slot(*this,
&HelloWorld::on_button_clicked));
add(m_button);
m_button.show();
}
HelloWorld::~HelloWorld() {}
void HelloWorld::on_button_clicked() {
cout << "Hello, world!" << endl;
}
int main (int argc, char *argv[]) {
Gtk::Main kit(argc, argv);
HelloWorld helloworld;
Gtk::Main::run(helloworld);
}
- Java
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);
}
}
- Java applet
Java applets[?] work in conjunction with HTML files.
<HTML>
<HEAD>
<TITLE>Hello World</TITLE>
</HEAD>
<BODY>
HelloWorld Program says:
<APPLET CODE="HelloWorld.class" WIDTH=600 HEIGHT=100>
</APPLET>
</BODY>
</HTML>
import java.applet.*;
import java.awt.*;
public class HelloWorld extends Applet {
public void paint(Graphics g) {
g.drawString("Hello, world!", 100, 50);
}
}
- JavaScript
JavaScript is a scripting language used in HTML files. To demo this program Cut and Paste the following code into any HTML file.
<script language="javascript">
function helloWorld()
{
javascript: alert("Hello World");
}
</script>
<a class=encyclopedia href="javascript:this.location()"
onclick="javascript:helloWorld();">Hello World Example</a>
- An easier method uses JavaScript implicitly, calling the reserved alert function. Cut and paste the following line inside the <BODY> .... </BODY> HTML tags.
<a class=encyclopedia href="#" onclick="alert('Hello World')">Hello World Example</a>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"> <box align="center"> <label value="Hello, world!" /> </box> </window>
Document Formats
<HTML> <HEAD> <TITLE>Hello, world!</TITLE> </HEAD> <BODY> Hello, world! </BODY> </HTML>
/font /Courier findfont 24 scalefont font setfont 100 100 moveto (Hello World!) show showpage
"Hello World" CS In-Joke
Non-CS Manager
mail -s "Hello, world." joe@b12 Joe, could you please write me a program that prints "Hello, world."? I need it by tomorrow. ^D
Non-CS Senior Manager
% zmail jim I need a "Hello, world." program by this afternoon.
Chief Executive
% letter letter: Command not found. % mail To: ^X ^F ^C % help mail help: Command not found. % damn! !: Event unrecognized % logout
See also:
- Hello, World! Page (http://www.latech.edu/~acm/HelloWorld.shtml).
All Wikipedia text is available under the terms of the GNU Free Documentation License
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