NAME

rand, srand − simple random number generator

SYNOPSIS

/usr/ucb/cc [ flag ... ] file ...

int rand(void);

int srand(unsigned seed);

DESCRIPTION

rand() uses a multiplicative congruential random number generator with period 232 to return successive pseudo-random numbers in the range from 0 to "231 −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. 

SEE ALSO

drand48(3C), rand(3C), random(3B)

NOTES

The spectral properties of rand() leave a great deal to be desired.  drand48(3C) and random(3B) provide much better, though more elaborate, random-number generators. 

The low bits of the numbers generated are not very random; use the middle bits.  In particular the lowest bit alternates between 0 and 1. 

SunOS 5.1/x86  —  Last change: 6 Jun 1991