srand
(PHP 3, PHP 4 , PHP 5)
srand -- Seed the random number generator
Description
void
srand ( [int seed])
Seeds the random number generator with seed.
Since PHP 4.2.0, the seed
becomes optional and defaults to a random value if omitted.
範例 1. srand() example
<?php // seed with microseconds function make_seed() { list($usec, $sec) = explode(' ', microtime()); return (float) $sec + ((float) $usec * 100000); } srand(make_seed()); $randval = rand(); ?>
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注: 由PHP 4.2.0 始,您不需要再使用 srand() 或 mt_srand() 為亂數產生器提供種子,因為這已自動的提供了。
See also:
rand(),
getrandmax(), and
mt_srand().