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MEMSHUFFLE(3)                C Programmer's Manual               MEMSHUFFLE(3)

NAME
       memshuffle - make an array be in random order

SYNOPSIS
       #include <publib.h>
       void *memshuffle(void *block, size_t elsize, size_t elnum);

DESCRIPTION
       memshuffle will move around the elements of an array in a random
       fashion.  It uses the standard library function rand(3) to get the
       pseudo-random numbers it needs.  The caller must set a suitable seed
       with srand(3).

RETURN VALUE
       memshuffle returns its first argument.

EXAMPLE
       To shuffle an integer array one might do the following.

            int array[4] = { 1, 2, 3, 4 };

            memshuffle(array, sizeof(array[0]), 4);

BUGS
       On many systems rand(3) is not of very good quality.  However, it is
       the only random number generator that can be assumed to exist.  Making
       it possible for the caller to provide an alternate source of random
       numbers (e.g., via a function pointer) is perhaps too more trouble than
       its worth.  A better way would be for everyone to fix their rand's.

SEE ALSO
       publib(3), memrev(3), rand(3), srand(3)

AUTHOR
       Lars Wirzenius (lars.wirzenius@helsinki.fi)

Publib                       C Programmer's Manual               MEMSHUFFLE(3)