10 PRINT "HELLO WORLD" 20 END

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

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

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


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

 #include <iostream.h>
  #include <string.h>
  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);
  }

  [
  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
", 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);
  }

#!/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;

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

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

  % echo "Hello, world."

 10 PRINT "HELLO WORLD"
END

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

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

  % letter
  letter: Command not found.
  % mail
  To: ^X ^F ^C
  % help mail
  help: Command not found.
  % damn!
  !: Event unrecognized
  % logout

package fac
func Factorial(n int) int {    res := 1
    for i := 1; i <= n; i++ {        res *= i    }
    return res}

package fac
func Factorial(n int) int {    if n == 0 {        return 1    } else {        return Factorial(n - 1) * n    }}

package fac
func Factorial(n interface{}) interface{} {    v, valid := n.(int)    if !valid {        return 0    }
    res := 1
    for i := 1; i <= v; i++ {        res *= i    }
    return res}

 package fac
import "sync"
func Factorial(n int) int {    var (        left, right = 1, 1        wg sync.WaitGroup    )
    wg.Add(2)
    pivot := n / 2
    go func() {        for i := 1; i < pivot; i++ {            left *= i        }
        wg.Done()    }()
    go func() {        for i := pivot; i <= n; i++ {            right *= i        }
        wg.Done()    }()
    wg.Wait()
    return left * right}

package fac
func Factorial(n int) <-chan int {    ch := make(chan int)
    go func() {        prev := 1
        for i := 1; i <= n; i++ {            v := prev * i
            ch <- v
            prev = v        }
        close(ch)    }()
    return ch}

package fac
/** * @see https://en.wikipedia.org/wiki/Factorial */type IFactorial interface {    CalculateFactorial() int}
// FactorialImpl implements IFactorial.var _ IFactorial = (*FactorialImpl)(nil)
/** * Used to find factorial of the n. */type FactorialImpl struct {    /**     * The n.     */    n int}
/** * Constructor of the FactorialImpl. * * @param n the n. */func NewFactorial(n int) *FactorialImpl {    return &FactorialImpl{        n: n,    }}
/** * Gets the n to use in factorial function. * * @return int. */func (this *FactorialImpl) GetN() int {    return this.n}
/** * Sets the n to use in factorial function. * * @param n the n. * @return void. */func (this *FactorialImpl) SetN(n int) {    this.n = n}
/** * Returns factorial of the n. * * @todo remove "if" statement. Maybe we should use a factory or somthing? * * @return int. */func (this *FactorialImpl) CalculateFactorial() int {    if this.n == 0 {        return 1    }
    n := this.n    this.n = this.n - 1
    return this.CalculateFactorial() * n}

package fac
// Factorial returns !n.func Factorial(n int) int {    res := 1
    for i := 1; i <= n; i++ {        res *= i    }
    return res}

package fac
// Factorial returns !n.func Factorial(n int) int {    res := 1
    for i := 1; i <= n; i++ {        res *= i    }
    return res}