term% cat index.txt RAND(3) Library Functions Manual RAND(3)
NAME
rand, lrand, frand, nrand, srand - random number generator
SYNOPSIS
int rand( )
long lrand( )
double frand( )
int nrand(val)
int val;
srand(seed)
int seed;
DESCRIPTION
Rand uses a polynominal feedback random number generator with period
2^49-2^32 to return successive uniform pseudo-random numbers x,
0<=x<2^15.
Lrand returns a uniform long x, 0<=x<2^31.
Frand returns a uniform double x, 0.0<=x<1.0.
Nrand returns a uniform integer x, 0<=x<val.
The generators are initialized by calling srand with whatever you like
as argument. To get a different starting value each time,
srand((int)time(0))
should work as long as it is not called more often than once per sec‐
ond.
BUGS
Rand and lrand are quite machine-dependent. In principle frand and
nrand are more portable, but only the Eighth Edition has them.
RAND(3)