Re: Zufallszahl in C

Lepton — Thu, 05 Aug 2004 18:54:13 GMT

DevC++
http://www.bloodshed.net/dev/devcpp.html

Basiert auf gcc, für Windows.

Re(2): Zufallszahl in C

Valen314 — Thu, 05 Aug 2004 18:49:45 GMT

ah ja... der icc ist soviel ich weiß nicht frei verfügbar...

Re: Zufallszahl in C

Valen314 — Thu, 05 Aug 2004 18:49:00 GMT

icc (intel c compiler)

aber mir persönlich gefällt VS Visual Studio.Net 2003 ganz gut... auch wenn ich dort eher den C# teil verwendet hab

Re(5): Zufallszahl in C

West — Thu, 05 Aug 2004 15:19:38 GMT

>

> ja, das kenn ich, die ideen muss man meistens selber haben ---- aus

Re(4): Zufallszahl in C

Norwegische Schmalzkatze — Thu, 05 Aug 2004 13:33:37 GMT

ja, das kenn ich, die ideen muss man meistens selber haben

Re(3): Zufallszahl in C

West — Thu, 05 Aug 2004 12:58:25 GMT

http://msdn.microsoft.com/visualc/vctoolkit2003/

es ist aber keine IDE dabei!

Re(2): Zufallszahl in C

Lunzi86 — Thu, 05 Aug 2004 12:34:27 GMT

Echt, hört sich interessant an, wo bekomm i den her?

Re(4): Zufallszahl in C

Lunzi86 — Thu, 05 Aug 2004 12:34:00 GMT

Ja, da brauch i jetzt abisl, das i mi da durcharbeit *g* (vorallem meit meim Engli.)

Aber dankeschön!

Re: Zufallszahl in C

West — Thu, 05 Aug 2004 12:31:37 GMT

Falls Du für Windows programmieren willst, es gibt jetzt auch ein Mini-Mini Developer Kit vom Microsoft C Compiler, der wird für MS Systeme schneller sein als der GNU.

Re(3): Zufallszahl in C

Robert Craven — Thu, 05 Aug 2004 12:25:09 GMT

Google -> "C rand" -> erster Treffer:
http://userpage.fu-berlin.de/~ram/pub/pub_kfd8tk88g/c_mischfunktion_de

Aber ja, x=rand()

Re(3): Zufallszahl in C

West — Thu, 05 Aug 2004 12:23:25 GMT

Lt. der GNU Documentation wie folgt:

NAME
     rand, srand - bad random number generator

SYNOPSIS
     #include

     void
     srand(unsigned seed);

     int
     rand(void);

     int
     rand_r(unsigned int *seed);

DESCRIPTION
     These interfaces are obsoleted by random(3).

     The rand() function computes a sequence of pseudo-random integers in the
     range of 0 to RAND_MAX (as defined by the header file ).

     The srand() function sets its argument as the seed for a new sequence of
     pseudo-random numbers to be returned by rand().  These sequences are re-
     peatable by calling srand() with the same seed value.

     If no seed value is provided, the functions are automatically seeded with
     a value of 1.

     The rand_r() is a thread-safe version of rand().  Storage for the seed
     must be provided through the seed argument, and needs to have been ini-
     tialized by the caller.

SEE ALSO
     arc4random(3),  rand48(3),  random(3)

STANDARDS
     The rand() and srand() functions conform to ANSI X3.159-1989 (``ANSI
     C'').

     The rand_r() function conforms to ISO/IEC 9945-1 ANSI/IEEE (``POSIX'')
     Std 1003.1c Draft 10.

<===================  RANDOM =================>

RANDOM(3)                 OpenBSD Programmer's Manual                RANDOM(3)

NAME
     random, srandom, initstate, setstate - better random number generator;
     routines for changing generators

SYNOPSIS
     #include

     long
     random(void);

     void
     srandom(unsigned int seed);

     char *
     initstate(unsigned int seed, char *state, size_t n);

     char *
     setstate(const char *state);

DESCRIPTION
     The random() function uses a non-linear additive feedback random number
     generator employing a default table of size 31 long integers to return
     successive pseudo-random numbers in the range from 0 to (2**31)-1.  The
     maximum value returned by random() is LONG_MAX (as defined by the header
     file ). The period of this random number generator is very
     large, approximately 16*((2**31)-1.

     The random()/ srandom() have (almost) the same calling sequence and ini-
     tialization properties as rand(3)/ srand(3).   The difference is that
     rand produces a much less random sequence -- in fact, the low dozen bits
     generated by rand go through a cyclic pattern.  All the bits generated by
     random() are usable.  For example, `random()&01' will produce a random
     binary value.

     Unlike srand,  srandom() does not return the old seed; the reason for
     this is that the amount of state information used is much more than a
     single word.  (Two other routines are provided to deal with restart-
     ing/changing random number generators).  Like rand(3),  however, random()
     will by default produce a sequence of numbers that can be duplicated by
     calling srandom() with `1' as the seed.

     The initstate() routine allows a state array, passed in as an argument,
     to be initialized for future use.  The size of the state array (in bytes)
     is used by initstate() to decide how sophisticated a random number gener-
     ator it should use -- the more state, the better the random numbers will
     be.  (Current "optimal" values for the amount of state information are 8,
     32, 64, 128, and 256 bytes; other amounts will be rounded down to the
     nearest known amount.  Using less than 8 bytes will cause an error.)  The
     seed for the initialization (which specifies a starting point for the
     random number sequence, and provides for restarting at the same point) is
     also an argument.  The initstate() function returns a pointer to the pre-
     vious state information array.

     Once a state has been initialized, the setstate() routine provides for
     rapid switching between states.  The setstate() function returns a point-
     er to the previous state array; its argument state array is used for fur-
     ther random number generation until the next call to initstate() or
     setstate().

     Once a state array has been initialized, it may be restarted at a differ-
     ent point either by calling initstate() (with the desired seed, the state
     array, and its size) or by calling both setstate() (with the state array)
     and srandom() (with the desired seed).  The advantage of calling both
     setstate() and srandom() is that the size of the state array does not
     have to be remembered after it is initialized.

     With 256 bytes of state information, the period of the random number gen-
     erator is greater than 2**69 which should be sufficient for most purpos-
     es.

AUTHOR
     Earl T. Cohen

DIAGNOSTICS
     If initstate() is called with less than 8 bytes of state information, or
     if setstate() detects that the state information has been garbled, error
     messages are printed on the standard error output.

SEE ALSO
     arc4random(3),  drand48(3),  rand(3)

STANDARDS
     The random(), srandom(), initstate(), and setstate() functions conform to
     X/Open Portability Guide Issue 4.2 (``XPG4.2'').

HISTORY
     These functions appeared in 4.2BSD.

BUGS
     About 2/3 the speed of rand(3).

Re(2): Zufallszahl in C

Lunzi86 — Thu, 05 Aug 2004 12:19:07 GMT

Wie wird das verwendet??

...
x = rand;
...

und den Compiler muss ich mir noch anschaun.
Aber dankeschön!!

PS: Wie kann man sowas selbst programmieren???

Re: Zufallszahl in C

Robert Craven — Thu, 05 Aug 2004 12:04:29 GMT

1) rand - oder sollst selber einen Zufallszahlengenerator programmieren?
2) http://gcc.gnu.org/

Zufallszahl in C

Lunzi86 — Thu, 05 Aug 2004 11:55:00 GMT

Hi Leutens!

Hab nicht grad viel ahnung in C, aber wie Programmiert man eine Zufallszahl? Wär echt lässig wenn ihr mir helfen könnt!

PS: Weiß irgendwer einen guten Compiler für C, ausser Borland c++BuilderX?