RAND(3) 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 linear feedback random number generator to
return uniform pseudo-random numbers x, 0<=x<2^15, with
period about 2^32.
Lrand returns a uniform long x, 0<=x<2^31, with period about
2^48.
Frand returns a uniform double x, 0.0<=x<1.0, always a mul-
tiple of 2^-31.
Nrand returns a uniform integer x, 0<=x<val.
The generators are initialized by calling srand with what-
ever you like as argument. To get a different starting
value each time,
srand((int)time((long *)0));
will work as long as it is not called more often than once
per second.
BUGS
Rand and lrand are quite machine-dependent. Although frand
and nrand are more portable, they appear in few versions of
Unix.