Keskustelu: Ohjelmointikysymykset: C: Rand()

eli mun pitäis saada arvottuu luku 0-50.. miten onnistuis?

C:llä

#include <math.h>
rand()%51

juu kiitos :)

Muista sitten alustaa satunnaislukugeneraattori ensin. Lisätietoja C-oppaassa.

Taitaa muuten olla #include <stdlib.h>

Minusta randia voi jo pelkällä stdio:lla.

Väärin, TGunner.

man 3 rand kirjoitti:

NAME
       rand, rand_r, srand - pseudo-random number generator

SYNOPSIS
       #include <stdlib.h>

       int rand(void);

       int rand_r(unsigned int *seedp);

       void srand(unsigned int seed);

jne.

Ja muuten, T.M.:lle:

man 3 rand kirjoitti:

NOTES
       The  versions of rand() and srand() in the Linux C Library use the same
       random number generator as random() and srandom(), so  the  lower-order
       bits  should  be as random as the higher-order bits.  However, on older
       rand() implementations, and on  current  implementations  on  different
       systems,  the  lower-order  bits  are much less random than the higher-
       order bits.  Do not use this function in applications  intended  to  be
       portable when good randomness is needed.

       In  Numerical Recipes in C: The Art of Scientific Computing (William H.
       Press, Brian P. Flannery, Saul A. Teukolsky, William T. Vetterling; New
       York:  Cambridge University Press, 1992 (2nd ed., p. 277)), the follow-
       ing comments are made:
              "If you want to generate a random integer between 1 and 10,  you
              should always do it by using high-order bits, as in

                     j = 1 + (int) (10.0 * (rand() / (RAND_MAX + 1.0)));

              and never by anything resembling

                     j = 1 + (rand() % 10);

              (which uses lower-order bits)."

miksei noiden tagien sisällä voi käyttää b:tä putkassa :(