Uma das primeiras coisas que um aluno de programação de computadores costuma aprender em termos de interação com a máquina é fazê-la exibir a frase "ALO MUNDO!" ("HELLO WORLD!", em inglês), assim mesmo. O texto a seguir foi recolhido pelo professor Alexandre Sobrino, da Universidade Santa Cecília (Unisanta), que o publicou assim em seu website acadêmico:

"Hello World!": o velho programa com várias roupagens

Há tempos atrás, este divertido texto circulou em listas de discussão técnicas da Internet brasileira e, acredito, será apreciado por nossos alunos de Ciências da Computação. Tomei apenas a liberdade de traduzir os títulos dos estilos de programação, mas optei por manter intacto o restante do texto. Se você sabe um pouquinho de inglês técnico, garanto que você vai gostar!

A propósito... qual é o seu estilo?   :)

____________________________
Segundo Grau

10 PRINT "HELLO WORLD"
20 END
____________________________
Primeiro Ano de Faculdade

program Hello(input, output)
begin
writeln('Hello World');
end.
____________________________
Último Ano de Faculdade

(defun hello
(print
(cons 'Hello (list 'World))))
____________________________
Profissional em início de carreira

#include
void main(void)
{
char *message[] = {"Hello ", "World"};
int i;
for(i = 0; i < 2; ++i)
printf("%s", message[i]);
printf("\n");
}
____________________________
Profissional Esporádico

#include
#include

class string
{
private:
int size;
char *ptr;

public:
string() : size(0), ptr(new char('\0')) {}
string(const string &s) : size(s.size)
{
ptr = new char[size + 1];
strcpy(ptr, s.ptr);
}

~string()
{
delete [] ptr;
}

friend ostream &operator <<(ostream &, const string &);
string &operator=(const char *);
};

ostream &operator<<(ostream &stream, const string &s)
{
return(stream << s.ptr);
}
string &string::operator=(const char *chrs)
{
if (this != &chrs)
{
delete [] ptr;
size = strlen(chrs);
ptr = new char[size + 1];
strcpy(ptr, chrs);
}
return(*this);
}
int main()
{
string str;

str = "Hello World";
cout << str << endl;

return(0);
}
____________________________
Programador Master

[
uuid(2573F8F4-CFEE-101A-9A9F-00AA00342820)
]
library LHello
{
// bring in the master library
importlib("actimp.tlb");
importlib("actexp.tlb");

// bring in my interfaces
#include "pshlo.idl"

[
uuid(2573F8F5-CFEE-101A-9A9F-00AA00342820)
]
cotype THello
{
interface IHello;
interface IPersistFile;
};
};

[
exe,
uuid(2573F890-CFEE-101A-9A9F-00AA00342820)
]
module CHelloLib
{

// some code related header files
importheader();
importheader();
importheader();
importheader("pshlo.h");
importheader("shlo.hxx");
importheader("mycls.hxx");

// needed typelibs
importlib("actimp.tlb");
importlib("actexp.tlb");
importlib("thlo.tlb");

[
uuid(2573F891-CFEE-101A-9A9F-00AA00342820),
aggregatable
]
coclass CHello
{
cotype THello;
};
};

#include "ipfix.hxx"
extern HANDLE hEvent;
class CHello : public CHelloBase
{
public:
IPFIX(CLSID_CHello);

CHello(IUnknown *pUnk);
~CHello();

HRESULT __stdcall PrintSz(LPWSTR pwszString);
private:
static int cObjRef;
};

#include
#include
#include
#include
#include "thlo.h"
#include "pshlo.h"
#include "shlo.hxx"
#include "mycls.hxx"

int CHello:cObjRef = 0;
CHello::CHello(IUnknown *pUnk) : CHelloBase(pUnk)
{
cObjRef++;
return;
}

HRESULT __stdcall CHello::PrintSz(LPWSTR pwszString)
{
printf("%ws\n", pwszString);
return(ResultFromScode(S_OK));
}

CHello::~CHello(void)
{

// when the object count goes to zero, stop the server
cObjRef--;
if( cObjRef == 0 )
PulseEvent(hEvent);

return;
}

#include
#include
#include "pshlo.h"
#include "shlo.hxx"
#include "mycls.hxx"

HANDLE hEvent;

int _cdecl main(
int argc,
char * argv[]
) {
ULONG ulRef;
DWORD dwRegistration;
CHelloCF *pCF = new CHelloCF();

hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

// Initialize the OLE libraries
CoInitiali, NULL);

// Initialize the OLE libraries
CoInitializeEx(NULL, COINIT_MULTITHREADED);

CoRegisterClassObject(CLSID_CHello, pCF,
CLSCTX_LOCAL_SERVER,
REGCLS_MULTIPLEUSE, &dwRegistration);

// wait on an event to stop
WaitForSingleObject(hEvent, INFINITE);

// revoke and release the class object
CoRevokeClassObject(dwRegistration);
ulRef = pCF->Release();

// Tell OLE we are going away.
CoUninitialize();

return(0); }

extern CLSID CLSID_CHello;
extern UUID LIBID_CHelloLib;

CLSID CLSID_CHello = { /*
2573F891-CFEE-101A-9A9F-00AA00342820 */
0x2573F891,
0xCFEE,
0x101A,
{ 0x9A, 0x9F, 0x00, 0xAA, 0x00, 0x34, 0x28, 0x20 }
};

UUID LIBID_CHelloLib = { /*
2573F890-CFEE-101A-9A9F-00AA00342820 */
0x2573F890,
0xCFEE,
0x101A,
{ 0x9A, 0x9F, 0x00, 0xAA, 0x00, 0x34, 0x28, 0x20 }
};

#include
#include
#include
#include
#include
#include "pshlo.h"
#include "shlo.hxx"
#include "clsid.h"

int _cdecl main(
int argc,
char * argv[]
) {
HRESULT hRslt;
IHello *pHello;
ULONG ulCnt;
IMoniker * pmk;
WCHAR wcsT[_MAX_PATH];
WCHAR wcsPath[2 * _MAX_PATH];

// get object path
wcsPath[0] = '\0';
wcsT[0] = '\0';
if( argc 1) {
mbstowcs(wcsPath, argv[1], strlen(argv[1]) + 1);
wcsupr(wcsPath);
}
else {
fprintf(stderr, "Object path must be specified\n");
return(1);
}

// get print string
if(argc 2)
mbstowcs(wcsT, argv[2], strlen(argv[2]) + 1);
else
wcscpy(wcsT, L"Hello World");

printf("Linking to object %ws\n", wcsPath);
printf("Text String %ws\n", wcsT);

// Initialize the OLE libraries
hRslt = CoInitializeEx(NULL, COINIT_MULTITHREADED);

if(SUCCEEDED(hRslt)) {

hRslt = CreateFileMoniker(wcsPath, &pmk);
if(SUCCEEDED(hRslt))
hRslt = BindMoniker(pmk, 0, IID_IHello, (void **)&pHello);

if(SUCCEEDED(hRslt)) {

// print a string out
pHello->PrintSz(wcsT);

Sleep(2000);
ulCnt = pHello->Release();
}
else
printf("Failure to connect, status: %lx", hRslt);

// Tell OLE we are going away.
CoUninitialize();
}

return(0);
}

____________________________
Aprendiz de Hacker

#!/usr/local/bin/perl
$msg="Hello, world.\n";
if ($#ARGV >= 0) {
while(defined($arg=shift(@ARGV))) {
$outfilename = $arg;
open(FILE, ">" . $outfilename) || die "Can't write $arg: $!\n";
print (FILE $msg);
close(FILE) || die "Can't close $arg: $!\n";
}
} else {
print ($msg);
}
1;

____________________________
Hacker Experiente

#include
#define S "Hello, World\n"
main(){exit(printf(S) == strlen(S) ? 0 : 1);}

____________________________
Hacker Esporádico

% cc -o a.out ~/src/misc/hw/hw.c
% a.out

____________________________
Guru Hacker

% cat
Hello, world.
^D

____________________________
Programador System AXE

LL0:
.seg "data"
.seg "text"
.proc 04
.global _main
_main:
!#PROLOGUE# 0
sethi %hi(LF26),%g1
add %g1,%lo(LF26),%g1
save %sp,%g1,%sp
!#PROLOGUE# 1
.seg "data1"
L30:
.ascii "Hello, World\012\0"
.seg "text"
.seg "data1"
L32:
.ascii "Hello, World\012\0"
.seg "text"
set L32,%o0
call _strlen,1
nop
mov %o0,%i5
set L30,%o0
call _printf,1
nop
cmp %o0,%i5
bne L2000000
nop
mov 0,%o0
b L2000001
nop
L2000000:
mov 0x1,%o0
L2000001:
call _exit,1
nop
LE26:
ret
restore
LF26 = -96
LP26 = 96
LST26 = 96
LT26 = 96
.seg "data"

0000000 0103 0107 0000 0060 0000 0020 0000 0000
0000020 0000 0030 0000 0000 0000 0054 0000 0000
0000040 033f ffff 8200 63a0 9de3 8001 1100 0000
0000060 9012 2000 4000 0000 0100 0000 ba10 0008
0000100 1100 0000 9012 2000 4000 0000 0100 00 ba10 0008
0000100 1100 0000 9012 2000 4000 0000 0100 0000
0000120 80a2 001d 1280 0005 0100 0000 9010 2000
0000140 1080 0003 0100 0000 9010 2001 4000 0000
0000160 0100 0000 81c7 e008 81e8 0000 0000 0000
0000200 4865 6c6c 6f2c 2057 6f72 6c64 0a00 4865
0000220 6c6c 6f2c 2057 6f72 6c64 0a00 0000 0000
0000240 0000 000c 0000 0608 0000 006e 0000 0010
0000260 0000 060b 0000 006e 0000 0014 0000 0286
0000300 ffff ffec 0000 0020 0000 0608 0000 0060
0000320 0000 0024 0000 060b 0000 0060 0000 0028
0000340 0000 0186 ffff ffd8 0000 004c 0000 0386
0000360 ffff ffb4 0000 0004 0500 0000 0000 0000
0000400 0000 000a 0100 0000 0000 0000 0000 0012
0000420 0100 0000 0000 0000 0000 001a 0100 0000
0000440 0000 0000 0000 0020 5f6d 6169 6e00 5f70
0000460 7269 6e74 6600 5f73 7472 6c65 6e00 5f65
0000500 7869 7400
0000504

% axe_generate -f system.uhdl
Application 'Exchange' generated
2324042350000000 source code lines
No Errors detected.
Hardware retrieval...done OK
Certification Test...done OK
Packing..............done OK
Delivery.............done OK
Application 'Exchange' delivered to customer
23456000 bytes/sec.
End processing, 2345 seconds.

___________________________
Programador de Altíssimo Nível

system.uhdl:

SYSTEM
CREATE ScreenWin
SIZE 20000000/Unit=One
DESTINATION Order.dest[One]
OUTPUT CHARACTER['Hello world']
END
END
____________________________
O Novo Gerente

10 PRINT "HELLO WORLD"
20 END
____________________________
O Gerente Médio

mail -s "Hello, world." bob@b12

Bob, could you please write me a program that prints
"Hello, world."? I need it by tomorrow.

^D
____________________________
O Gerente de Nível Mais Alto

% zmail all

I need a "Hello, world." program by this afternoon.

____________________________
Chefe Executivo

% message
message: Command not found
% pm
pm: Command not found
% letter
letter: Command not found.
% mail
To: ^X ^F ^C
help mail
help: Command not found.
>what
what: Command not found
>need help
need: Command not found
damn!
!: Event unrecognized
>exit
exit: Unknown
>quit
%
% logout

Bipppp! Mrs. Thomsson? Please page Tommy for me. NOW!