发人深思，耐人寻味：The Evolution of a Programmer

High School/Jr.High

  10 PRINT "HELLO WORLD"
  20 END

First year in College

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

Senior year in College

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

New professional

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

Seasoned professional

  #include 
  #include 
 
  class string
  {
  private:
    int size;
    char *ptr;
 
  string() : size(0), ptr(new char[1]) { ptr[0] = 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);
  }

Master Programmer

  [
  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
", 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
  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);
  }

Apprentice 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;

Experienced Hacker

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

Seasoned Hacker

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

Guru Hacker

  % echo "Hello, world."

New Manager

  10 PRINT "HELLO WORLD"
  20 END

Middle Manager

  mail -s "Hello, world." bob@b12
  Bob, could you please write me a program that prints "Hello, world."?
  I need it by tomorrow.
  ^D

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