The hello world program
A "hello world" program is a computer program that simply prints out "Hello, world!". It is used in many introductory tutorials for teaching a programming language and many students use it as their first programming experience in a language. A "hello world" program is typically one of the simpler programs possible in a computer language. Some are surprisingly complex, especially in some Graphical User Interface (GUI) contexts. Some others are surprisingly simple, especially those which heavily rely on a particular shell to perform the actual output.
A "hello world" program can be a useful sanity test to make sure that a language's compiler , development environment , and run-time environment are correctly installed. 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 small test programs existed since the development of programmable computers , the tradition of using the phrase "Hello, world!" as the test message was influenced by an example program in the book The C Programming Language , by Brian Kernighan and Dennis Ritchie . The example program from that book prints "hello, world" (i.e., no capital letters, no exclamation sign).
A collection of "hello world" programs written in various computer languages can serve as a simple "Rosetta Stone " to assist in learning and comparing the languages.
Here are some examples in different languages:
Line-oriented (aka Console)
WRITE "Hello World"
with Ada.Text_Io; use Ada.Text_Io;
procedure Hello is
begin
Put_Line ("Hello, world!");
end Hello;
PROC main()
WriteF('Hello, World!')
ENDPROC
'Hello World'
Accumulator-only architecture: DEC PDP-8 , PAL-III assembler
See the example section of the PDP-8 article .
First successful µP/OS combinations: Intel 8080 /Zilog Z80 , CP/M , RMAC assembler
bdos equ 0005H ; BDOS entry point
start: mvi c,9 ; BDOS function: output string
lxi d,msg$ ; address of msg
call bdos
ret ; return to CCP
msg$: db 'Hello, world!$'
end start
Accumulator + index register machine: MOS 6502 , CBM KERNAL , ca65 assembler
MSG: .ASCIIZ "Hello, world!"
LDX #0
LDA MSG,X ; load initial char
@LP: JSR $FFD2 ; chrout
INX
LDA MSG,X
BNE @LP
RTS
See the example section of the Nova article.
MODEL SMALL
IDEAL
STACK 100H
DATASEG
MSG DB 'Hello, world!$'
CODESEG
MOV AX, @data
MOV DS, AX
MOV DX, OFFSET MSG
MOV AH, 09H ; DOS: output ASCII$ string
INT 21H
MOV AX, 4C00H
INT 21H
END
General-purpose-register CISC: DEC PDP-11 , RT-11 , MACRO-11
.MCALL .REGDEF,.TTYOUT,.EXIT
.REGDEF
HELLO: MOV #MSG,R1
MOVB (R1),R0
LOOP: .TTYOUT
MOVB +(R1),R0
BNE LOOP
.EXIT
MSG: .ASCIZ /HELLO, WORLD!/
.END HELLO
CISC on advanced multiprocessing OS: VAX , VMS , MACRO32
.title hello
term_name: .ascid /SYS$INPUT/
term_chan: .blkw 1
out_iosb: .blkq 1
msg: .asciz /Hello, world!/
.entry start,0
; establish a channel for terminal I/O
$assign_s devnam=term_name,-
chan=term_chan
blbc r0,error
; queue the I/O request
$qio_s chan=term_chan,-
func=#io$_writevblk,-
iosb=out_iosb,-
p1=msg,-
p2=#13
blbc r0,error
$exit_s ; normal exit
error: halt ; error condition
.end start
.program
ADR R0,message
SWI "OS_Write0"
SWI "OS_Exit"
.message
DCS "Hello, world!"
DCB 0
ALIGN
BEGIN { print "Hello, world!" }
MS BASIC (traditional, unstructured)
10 PRINT "Hello, world!"
20 END
:Disp "Hello, world!"
sub main
print "Hello, World"
end sub
Structured BASIC
print "Hello, world!"
GET "LIBHDR"
LET START () BE
$(
WRITES ("Hello, world!*N")
$)
%TITLE 'HELLO_WORLD'
MODULE HELLO_WORLD (IDENT='V1.0', MAIN=HELLO_WORLD,
ADDRESSING_MODE (EXTERNAL=GENERAL)) =
BEGIN
LIBRARY 'SYS$LIBRARY:STARLET';
EXTERNAL ROUTINE
LIB$PUT_OUTPUT;
GLOBAL ROUTINE HELLO_WORLD =
BEGIN
LIB$PUT_OUTPUT(%ASCID %STRING('Hello World!'))
END;
END
ELUDOM
#include
int main(void) {
printf("Hello, world!\n");
return 0;
}
#include
int main() {
std::cout << "Hello, world!\n";
}
class HelloWorldApp {
public static void Main() {
System.Console.WriteLine("Hello, world!");
}
}
module hello
Start :: String
Start = "Hello, world"
PROC 0
WRITE Hello, World!
IDENTIFICATION DIVISION.
PROGRAM-ID. HELLO-WORLD.
ENVIRONMENT DIVISION.
DATA DIVISION.
PROCEDURE DIVISION.
DISPLAY "Hello, world!".
STOP RUN.
(format t "Hello world!~%")
$ write sys$output "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").
begin TOOL HelloWorld;
includes Framework;
HAS PROPERTY IsLibrary = FALSE;
forward Hello;
-- START CLASS DEFINITIONS
class Hello inherits from Framework.Object
has public method Init;
has property
shared=(allow=off, override=on);
transactional=(allow=off, override=on);
monitored=(allow=off, override=on);
distributed=(allow=off, override=on);
end class;
-- END CLASS DEFINITIONS
-- START METHOD DEFINITIONS
------------------------------------------------------------
method Hello.Init
begin
super.Init();
task.Part.LogMgr.PutLine('HelloWorld!');
end method;
-- END METHOD DEFINITIONS
HAS PROPERTY
CompatibilityLevel = 0;
ProjectType = APPLICATION;
Restricted = FALSE;
MultiThreaded = TRUE;
Internal = FALSE;
LibraryName = 'hellowor';
StartingMethod = (class = Hello, method = Init);
end HelloWorld;
." Hello, world!" CR
PROGRAM HELLO
WRITE(*,10)
10 FORMAT('Hello, world!')
STOP
END
module HelloWorld (main) where
main = putStr "Hello World\n"
ON ENTER {
"Hello, " "World!" & SAY
}
"Hello world!" print
or
write("Hello world!\n")
public class Hello {
public static void main(String[] args) {
System.out.println("Hello, world!");
}
}
print [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
@echo off
echo Hello, world!
let _ =
print_endline "Hello world!";;
PROC hello:
PRINT "Hello, World"
ENDP
(object-class request
^action)
(startup
(strategy MEA)
(make request ^action hello)
)
(rule hello
(request ^action hello)
-->
(write |Hello World!| (crlf))
)
program Hello;
begin
writeln('Hello, world!');
end.
print "Hello, world!\n";
#!/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;
print "Hello, world!"
say "Hello, world!"
puts "Hello, world!"
class HELLO_WORLD is
main is
#OUT+"Hello World\n";
end;
end;
(display "Hello, world!")
(newline)
sed (requires at least one line of input)
sed -ne '1s/.*/Hello, world!/p'
'Hello, World!' print.
Transcript show: 'Hello, world!'
print "Hello, world!\n";
OUTPUT = "Hello, world!"
END
create table MESSAGE (TEXT char(15));
insert into MESSAGE (TEXT) values ('Hello, world!');
select TEXT from MESSAGE;
drop table MESSAGE;
Or
select 'Hello, world' from dual;
Or, more simply
print 'Hello, World.'
puts "Hello, world!"
put "Hello, world!"
echo 'Hello, world!'
Algoritmul Salut este:
fie s:="Hello, world";
tipareste s;
sf-Salut
Graphical User Interfaces - as traditional applications
C++ bindings for GTK graphics toolkit
#include
#include
#include
#include
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);
return 0;
}
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);
}
}
#include
#include
#include
#include
class HelloWorld : public QWidget
{
Q_OBJECT
public:
HelloWorld();
virtual ~HelloWorld();
public slots:
void handleButtonClicked();
QPushButton *mPushButton;
};
HelloWorld::HelloWorld() :
QWidget(),
mPushButton(new QPushButton("Hello, World!", this))
{
connect(mPushButton, SIGNAL(clicked()), this, SLOT(handleButtonClicked()));
}
HelloWorld::~HelloWorld() {}
void HelloWorld::handleButtonClicked()
{
std::cout << "Hello, World!" << std::endl;
}
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
HelloWorld helloWorld;
app.setMainWidget(&helloWorld);
helloWorld.show();
return app.exec();
}
display dialog "Hello, world!"
MsgBox "Hello, world!"
#include
LRESULT CALLBACK WindowProcedure(HWND, UINT, WPARAM, LPARAM);
char szClassName[] = "MainWnd";
HINSTANCE hInstance;
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
HWND hwnd;
MSG msg;
WNDCLASSEX wincl;
hInstance = hInst;
wincl.cbSize = sizeof(WNDCLASSEX);
wincl.cbClsExtra = 0;
wincl.cbWndExtra = 0;
wincl.style = 0;
wincl.hInstance = hInstance;
wincl.lpszClassName = szClassName;
wincl.lpszMenuName = NULL; //No menu
wincl.lpfnWndProc = WindowProcedure;
wincl.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1); //Color of the window
wincl.hIcon = LoadIcon(NULL, IDI_APPLICATION); //EXE icon
wincl.hIconSm = LoadIcon(NULL, IDI_APPLICATION); //Small program icon
wincl.hCursor = LoadCursor(NULL, IDC_ARROW); //Cursor
if (!RegisterClassEx(&wincl))
return 0;
hwnd = CreateWindowEx(0, //No extended window styles
szClassName, //Class name
"", //Window caption
WS_OVERLAPPEDWINDOW & ~WS_MAXIMIZEBOX,
CW_USEDEFAULT, CW_USEDEFAULT, //Let Windows decide the left and top positions of the window
120, 50, //Width and height of the window,
NULL, NULL, hInstance, NULL);
//Make the window visible on the screen
ShowWindow(hwnd, nCmdShow);
//Run the message loop
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
switch (message)
{
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
TextOut(hdc, 15, 3, "Hello, world!", 13);
EndPaint(hwnd, &ps);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, message, wParam, lParam);
}
return 0;
}
Graphical User Interfaces - Web browser based
Java applets work in conjunction with HTML files.
Hello World
HelloWorld Program says:
import java.applet.*;
import java.awt.*;
public class HelloWorld extends Applet {
public void paint(Graphics g) {
g.drawString("Hello, world!", 100, 50);
}
}
JavaScript is a scripting language used in HTML files. To demo this program Cut and Paste the following code into any HTML file.
Hello World Example
An easier method uses JavaScript implicitly, calling the reserved alert function. Cut and paste the following line inside the .... HTML tags.
Hello World Example
An even easier method involves using popular browsers' support for the virtual 'javascript' protocol to execute JavaScript code. Enter the following as an Internet address (usually by pasting into the address box):
javascript:alert('Hello, world!')
Document Formats
The following sequence of characters, expressed in hexadecimal notation (with carriage return and newline characters at end of sequence):
48 65 6C 6C 6F 2C 20 77 6F 72 6C 64 21 0D 0A
Hello, world!
Hello, world!
/Courier findfont 24 scalefont setfont
100 100 moveto
(Hello world!) show
showpage
\font\HW=cmr10 scaled 3000
\leftline{\HW Hello world}
\bye
See also
External links
