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rand(3B)
simple random number generator
From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.
Also by this name: rand(3C), C library
NAME
rand, srand - simple random number generator
SYNOPSIS
cc [ flag... ] file ... -lucb srand(seed) int seed; rand()
DESCRIPTION
rand uses a multiplicative congruential random number generator with period 2**32 to return successive pseudo-random numbers in the range from 0 to (2**31)-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
random(3). drand48(2), drand(3C), rand(3C), srand(3C) in the Programmer's Reference Manual.
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.