NAME

rand, srand − simple random number generator

SYNOPSIS

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

srand(seed)
int seed;

rand()

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(2), drand(3C), rand(3C), random(3), srand(3C). 

NOTES

The spectral properties of rand leave a great deal to be desired.  drand48(2) and random(3) 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. 

  —  BSD Compatibility Package