rand(3C)

NAME

rand(), srand() − simple random-number generator

SYNOPSIS

#include <stdlib.h>

int rand(void);

void srand(unsigned int seed);

DESCRIPTION

rand() uses a multiplicative, congruential, random-number generator with period 232 that returns successive pseudo-random numbers in the range from 0 to 215−1.

srand() can be called at any time to reset the random-number generator to a random starting point. The generator is initially seeded with a value of 1.

NOTE

The spectral properties of rand() leave a great deal to be desired. drand48() provides a much better, though more elaborate, random-number generator (see drand48(3C)).

STANDARDS CONFORMANCE

rand(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C

srand(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C

Hewlett-Packard Company — HP-UX Release 9.0: August 1992

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