Forslag til kildekode på folie på glassvegg

factorial.lisp

(define factorial
    (lambda (n)
      (if (= n 0)
          1
          (* n (factorial (- n 1))))))

FRAMEADV.S

*-------------------------------
*
*  Draw entire 10 x 3 screen from scratch
*
*-------------------------------
SURE
 lda #1
 sta genCLS ;clear screen

 jsr setback ;draw on bg plane

 jsr getprev ;get 3 rightmost blocks of screen to left

 lda SCRNUM
 jsr calcblue ;get blueprint base addr

HelloWin311.c

/*--------------------------------------------------------
   HELLOWIN.C -- Displays "Hello, Windows" in client area
                 (c) Charles Petzold, 1990
  --------------------------------------------------------*/

#include <windows.h>

long FAR PASCAL WndProc (HWND, WORD, WORD, LONG) ;

int PASCAL WinMain (HANDLE hInstance, HANDLE hPrevInstance,
                    LPSTR lpszCmdParam, int nCmdShow)
     {
     static char szAppName[] = "HelloWin" ;
     HWND        hwnd ;
     MSG         msg ;
     WNDCLASS    wndclass ;

     if (!hPrevInstance)
          {
          wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
          wndclass.lpfnWndProc   = WndProc ;
          wndclass.cbClsExtra    = 0 ;
          wndclass.cbWndExtra    = 0 ;
          wndclass.hInstance     = hInstance ;
          wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
          wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
          wndclass.hbrBackground = GetStockObject (WHITE_BRUSH) ;
          wndclass.lpszMenuName  = NULL ;
          wndclass.lpszClassName = szAppName ;

          RegisterClass (&wndclass) ;
          }

     hwnd = CreateWindow (szAppName,         // window class name
                    "The Hello Program",     // window caption
                    WS_OVERLAPPEDWINDOW,     // window style
                    CW_USEDEFAULT,           // initial x position
                    CW_USEDEFAULT,           // initial y position
                    CW_USEDEFAULT,           // initial x size
                    CW_USEDEFAULT,           // initial y size
                    NULL,                    // parent window handle
                    NULL,                    // window menu handle
                    hInstance,               // program instance handle
                    NULL) ;	                 // creation parameters

     ShowWindow (hwnd, nCmdShow) ;
     UpdateWindow (hwnd) ;

     while (GetMessage (&msg, NULL, 0, 0))
          {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
          }
     return msg.wParam ;
     }

long FAR PASCAL WndProc (HWND hwnd, WORD message, WORD wParam, LONG lParam)
     {
     HDC         hdc ;
     PAINTSTRUCT ps ;
     RECT        rect ;

     switch (message)
          {
          case WM_PAINT:
               hdc = BeginPaint (hwnd, &ps) ;

               GetClientRect (hwnd, &rect) ;

               DrawText (hdc, "Hello, Windows!", -1, &rect,
                         DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;

               EndPaint (hwnd, &ps) ;
               return 0 ;

          case WM_DESTROY:
               PostQuitMessage (0) ;
               return 0 ;
          }

     return DefWindowProc (hwnd, message, wParam, lParam) ;
     }

Aside from the antique C syntax and the weird idiosyncratic formatting, I think most people would agree that compared with Microsoft's original, mine is a model of clarity and brevity.

Eventually I got tired of people complaining how long my "Hello World" program was, so Programming Windows, 5th edition (1998) began with this program:

/*--------------------------------------------------------------
   HelloMsg.c -- Displays "Hello, Windows 98!" in a message box
                 (c) Charles Petzold, 1998
  --------------------------------------------------------------*/

#include <windows.h>

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     MessageBox (NULL, TEXT ("Hello, Windows 98!"), TEXT ("HelloMsg"), 0) ;

     return 0 ;
}

LUNAR_LANDING_GUIDANCE_EQUATIONS.s

#************************************************************************
# ENTRY POINTS:  ?GUIDSUB FOR THE IGNITION ALGORITHM, LUNLAND FOR SERVOUT
#************************************************************************

# IGNITION ALGORITHM ENTRY:  DELIVERS N PASSES OF QUADRATIC GUIDANCE

?GUIDSUB	EXIT
		CAF	TWO		# N = 3
		TS	NGUIDSUB
		TCF	GUILDRET +2

GUIDSUB		TS	NGUIDSUB	# ON SUCCEEDING PASSES SKIP TTFINCR
		TCF	CALCRGVG

# NORMAL ENTRY:  CONTROL COMES HERE FROM SERVOUT

LUNLAND		TC	PHASCHNG
		OCT	00035		# GROUP 5:  RETAIN ONLY PIPA TASK
		TC	PHASCHNG
		OCT	05023		# GROUP 3:  PROTECT GUIDANCE WITH PRIO 21  
		OCT	21000		#	JUST HIGHER THAN SERVICER'S PRIORITY

Q_rsqrt.c

float Q_rsqrt( float number )
{
	long i;
	float x2, y;
	const float threehalfs = 1.5F;

	x2 = number * 0.5F;
	y  = number;
	i  = * ( long * ) &y;                       // evil floating point bit level hacking
	i  = 0x5f3759df - ( i >> 1 );               // what the fuck? 
	y  = * ( float * ) &i;
	y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
//	y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

	return y;
}

let (|>) x f = f x

DEFINE qsort == [small] [] [uncons [>] split] [enconcat] binrec.

Quicksort i Joy

(defun Y (f)
  ((lambda (x) (funcall x x))
   (lambda (y)
     (funcall f (lambda (&rest args)
          (apply (funcall y y) args))))))

Y-combinator i CommonLisp

Fibonacci i Haskell

fibs = 1 : 1 : zipWith (+) fibs (tail fibs)

http://www.ibiblio.org/apollo/listings/Luminary099/BURN_BABY_BURN--MASTER_IGNITION_ROUTINE.agc.html

Swap to varibaler uten en temp-variabel:

a^=b;
b^=a;
a^=b;

Vent på vertical retrace:

    mov     dx,03dah
waitstart:      
    in      al,dx
    and     al,08h
    jnz     waitstart
waitend:            
    in      al,dx
    and     al,08h
    jz      waitend

Bresenhams algoritme:

void line(int x0, int y0, int x1, int y1) {

  int dx = abs(x1-x0), sx = x0<x1 ? 1 : -1;
  int dy = abs(y1-y0), sy = y0<y1 ? 1 : -1; 
  int err = (dx>dy ? dx : -dy)/2, e2;

  for(;;){
    setPixel(x0,y0);
    if (x0==x1 && y0==y1) break;
    e2 = err;
    if (e2 >-dx) { err -= dy; x0 += sx; }
    if (e2 < dy) { err += dx; y0 += sy; }
  }
}

FFT:

def fft(x):
    N = len(x)
    if N <= 1: return x
    even = fft(x[0::2])
    odd =  fft(x[1::2])
    T= [exp(-2j*pi*k/N)*odd[k] for k in range(N//2)]
    return [even[k] + T[k] for k in range(N//2)] + [even[k] - T[k] for k in range(N//2)]

Robert'); DROP TABLE students; --