[unix-history] / man / man3 / rand.3

.th RAND III 1/15/73
.sh NAME
rand \*- random number generator
.sh SYNOPSIS
(seed in r0)
.br
.ft B
jsr	pc,srand	/to initialize
.s3
jsr pc,rand	/to get a random number
.s3
.nf
srand(seed)
int seed;
.s3
rand( )
.fi
.ft R
.s3
.sh DESCRIPTION
.it Rand
uses a multiplicative congruential
random number generator to return successive pseudo-random
numbers (in r0) in the range from 1 to 2\u\s715\s10\d\*-1.
.s3
The generator is reinitialized by calling
.it srand
with 1 as argument (in r0).
It can be set to a random starting point by calling
.it srand
with whatever you like as argument,
for example the low-order word
of the time.
.sh WARNING
The author of this routine has been writing
random-number generators for many years and has never been
known to write one that worked.
.sh BUGS
The low-order bits are not very random.
Commit	Line	Data
8ac21c23 KT	1	.th RAND III 1/15/73
	2	.sh NAME
	3	rand \*- random number generator
	4	.sh SYNOPSIS
	5	(seed in r0)
	6	.br
	7	.ft B
	8	jsr pc,srand /to initialize
	9	.s3
	10	jsr pc,rand /to get a random number
	11	.s3
	12	.nf
	13	srand(seed)
	14	int seed;
	15	.s3
	16	rand( )
	17	.fi
	18	.ft R
	19	.s3
	20	.sh DESCRIPTION
	21	.it Rand
	22	uses a multiplicative congruential
	23	random number generator to return successive pseudo-random
	24	numbers (in r0) in the range from 1 to 2\u\s715\s10\d\*-1.
	25	.s3
	26	The generator is reinitialized by calling
	27	.it srand
	28	with 1 as argument (in r0).
	29	It can be set to a random starting point by calling
	30	.it srand
	31	with whatever you like as argument,
	32	for example the low-order word
	33	of the time.
	34	.sh WARNING
	35	The author of this routine has been writing
	36	random-number generators for many years and has never been
	37	known to write one that worked.
	38	.sh BUGS
	39	The low-order bits are not very random.