Progrma 'hello world'

He aquí unos ejemplos de programas que despliegan 'Hello World' escritos por personas en las diferentes etapas de su carrera profesional:

(un programa que despliegue "hello world" es el primero que generalmente hace un programador hace al conocer un nuevo lenguaje o técnica de programación)

Al salir de bachillerato:

10 PRINT "HELLO WORLD"
20 END

Primer año en la universidad:

program Hello(input, output)
begin
writeln('Hello World')
end.

Ultimos años en la universidad:

(defun hello
(print
(cons 'Hello (list 'World))))

Nuevo profesional:

#include <stdio.h>
void main(void)
{
char *message[] = {"Hello ", "World"};
int i;

for(i = 0; i < 2; ++i)
printf("%s", message[i]);
printf("\n");
}

Profesional tomando experiencia:

#include <iostream.h>
#include <string.h>

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 con mucha experiencia:

[
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(<windows.h>);
    importheader(<ole2.h>);
    importheader(<except.hxx>);
    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 <windows.h>
#include <ole2.h>
#include <stdio.h>
#include <stdlib.h>
#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 <windows.h>
#include <ole2.h>
#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
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 <windows.h>
#include <ole2.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#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);
}

Hacker aprendiendo:

#!/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;