rand.3

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3 代码 · 共 46 行

.\" SCCSID: @(#)rand.3	8.2	1/28/91
.TH rand 3
.SH Name
rand, srand \- random number generator
.SH Syntax
.nf
.B #include <stdlib.h>
.PP
.B void srand(\fIseed\fP)
.B unsigned \fIseed\fP; 
.PP
.B rand()
.fi
.SH Description
The newer 
.MS random 3
should be used in new applications.
.NXR "rand subroutine (standard C)"
.NXR "srand subroutine"
.NXA "rand subroutine (standard C)" "random subroutine"
.NXR "random number generator"
The
.PN rand
subroutine remains for compatibility.
.PP
The
.PN rand
subroutine uses a multiplicative congruential
random number generator
with period 2\u\s732\s0\d
to return successive pseudo-random
numbers in the range from 0 to 2\u\s731\s10\d\-1.
.PP
The generator is reinitialized by calling
.PN srand
with 1 as argument.
It can be set to a random starting point by calling
.PN srand
with whatever you like as argument.
.SH Environment
For the System V environment, the
.PN rand
subroutine returns numbers in the range from 0 to 2\u\s715\s10\d\-1.
.SH See Also
random(3)