RAND(3) 1 RAND(3)rand - Generate a random integerSYNOPSIS
int rand (void )
DESCRIPTION
int rand (int $min, int $max)
If called without the optional $min, $max arguments rand(3) returns a pseudo-random integer between 0 and getrandmax(3). If you want a
random number between 5 and 15 (inclusive), for example, use rand(5, 15).
Caution
This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a
cryptographically secure value, consider using random_int(3), random_bytes(3), or openssl_random_pseudo_bytes(3) instead.
Note
On some platforms (such as Windows), getrandmax(3) is only 32767. If you require a range larger than 32767, specifying $min and
$max will allow you to create a range larger than this, or consider using mt_rand(3) instead.
PARAMETERS
o $min
- The lowest value to return (default: 0)
o $max
- The highest value to return (default: getrandmax(3))
RETURN VALUES
A pseudo random value between $min (or 0) and $max (or getrandmax(3), inclusive).
EXAMPLES
Example #1
rand(3) example
<?php
echo rand() . "
";
echo rand() . "
";
echo rand(5, 15);
?>
The above example will output something similar to:
7771
22264
11
SEE ALSO srand(3), getrandmax(3), mt_rand(3), random_int(3), random_bytes(3), openssl_random_pseudo_bytes(3).
PHP Documentation Group RAND(3)
Check Out this Related Man Page
RAND(3) Linux Programmer's Manual RAND(3)NAME
rand, srand - random number generator.
SYNOPSIS
#include <stdlib.h>
int rand(void);
void srand(unsigned int seed);
DESCRIPTION
The rand() function returns a pseudo-random integer between 0 and RAND_MAX.
The srand() function sets its argument as the seed for a new sequence of pseudo-random integers to be returned by rand(). These sequences
are repeatable by calling srand() with the same seed value.
If no seed value is provided, the rand() function is automatically seeded with a value of 1.
RETURN VALUE
The rand() function returns a value between 0 and RAND_MAX. The srand() returns no value.
NOTES
The versions of rand() and srand() in the Linux C Library use the same random number generator as random() and srandom(), so the lower-
order bits should be as random as the higher-order bits. However, on older rand() implementations, the lower-order bits are much less ran-
dom than the higher-order bits.
In Numerical Recipes in C: The Art of Scientific Computing (William H. Press, Brian P. Flannery, Saul A. Teukolsky, William T. Vetterling;
New York: Cambridge University Press, 1992 (2nd ed., p. 277)), the following comments are made:
"If you want to generate a random integer between 1 and 10, you should always do it by using high-order bits, as in
j=1+(int) (10.0*rand()/(RAND_MAX+1.0));
and never by anything resembling
j=1+(rand() % 10);
(which uses lower-order bits)."
Random-number generation is a complex topic. The Numerical Recipes in C book (see reference above) provides an excellent discussion of
practical random-number generation issues in Chapter 7 (Random Numbers).
For a more theoretical discussion which also covers many practical issues in depth, please see Chapter 3 (Random Numbers) in Donald E.
Knuth's The Art of Computer Programming, volume 2 (Seminumerical Algorithms), 2nd ed.; Reading, Massachusetts: Addison-Wesley Publishing
Company, 1981.
CONFORMING TO
SVID 3, BSD 4.3, ISO 9899
SEE ALSO random(3), srandom(3), initstate(3), setstate(3)GNU 1995-05-18 RAND(3)
hi
I want to get a rodom integer, but I just get the same integer while using the fuction rand() for the first time. So I wonder wether there is a way in which I can get an unknow random integer.
Thanks in advance (2 Replies)
Hi all,
Is the rand() function in C uniform or normal distribution. If it is unform, is there a random function that is normal.
Thanks and Regards (2 Replies)
HI all
I'm trying to write an awk script to print the min and max value in a range(s) contained in another file - the range values are in $2
EG
114,7964,1,y,y,n
114,7965,1,y,y,n
114,7966,1,y,y,n
114,7967,1,y,y,n
114,7969,1,y,y,n
114,7970,1,y,y,n
114,7971,1,y,y,n
114,7972,1,y,y,n... (3 Replies)
Hello every one, I have following data
***CAMPAIGN 1998 CONTRIBUTIONS***
---------------------------------------------------------------------------
NAME PHONE Jan | Feb | Mar | Total Donated
... (12 Replies)
can any one tell me how to create integer random no between 10 to 40 in C language.When i m using random() or rand() functions they r creting some
long int which is not required (5 Replies)
hi, i have an awk script and I managed to figure out how to search the max value but Im having difficulty in searching for the min field value.
BEGIN {FS=","; max=0}
NF == 7 {if (max < $6) max = $6;}
END { print man, min}
where $6 is the column of a field separated by a comma (3 Replies)
Hi,
I have a text file containing numbers. There are up to 6 numbers per row and I need to read them, check if they are 0 and if they are not zero check if they are within a given interval (min,max). If they exceed the max or min they should be set to max or min respectively, if they are in the... (4 Replies)
Is it possible to print max number of 2 columns - awk
note: print max if the integer is positive and print min if the integer is negative
input
a 1 2
b 3 4
c 5 1
d -3 -5
d -5 -3
output
a 2
b 4
c 5
d -5
d -5 (4 Replies)
Hello Experts,
I have got a txt files which has multiple columns, I want to get the max, min and diff (max-min) for each column in the same txt file. Example:
cat file.txt
a 1 4
b 2 5
c 3 6
I want ouput like:
cat file.txt
a 1 4
b 2 5
c 3 6
Max 3 6
Min 1 4
Diff 2 2
awk 'min=="" ||... (4 Replies)
I have to find the min and max on a specific column in a file after sending that column and one other to a output file but I keep getting a maximum of zero
below is what i have so far if anyone can give me advice on what i am doing wrong the help would be much appreciated
# ! /usr/bin/perl -w... (2 Replies)
Hi,
I have a string looks like the following:
USERS 32767.9844 UNDOTBS1 32767.9844 SYSAUX 32767.9844 SYSTEM 32767.9844 EMS 8192 EMS 8192 EMS_INDEXES 4096 EMS_INDEXES 4096 8 rows selected.
How do I extract a sub-string to get the expected output as following:
EMS 8192
EMS_INDEXES 4096
... (3 Replies)
Hi,
I have a file which looks like this:
FID IID MISS_PHENO N_MISS N_GENO F_MISS
12AB43131 12AB43131 N 17774 906341 0.01961
65HJ87451 65HJ87451 N 10149 906341 0.0112
43JJ21345 43JJ21345 N 2826 906341 0.003118I would... (11 Replies)
I need to find the max/min of columns 1 and 2 of a 2 column file what contains the special character ">".
I know that this will find the max value of column 1.
awk 'BEGIN {max = 0} {if ($1>max) max=$1} END {print max}' input.file
But what if I needed to ignore special characters in the... (3 Replies)
Hi,
I need your kind help to get min and max values from file based on value in $5 .
File1
SP12.3 stc 2240806 2240808 + ID1_N003 ID2_N003T0
SP12.3 sto 2241682 2241684 + ID1_N003 ID2_N003T0
SP12.3 XE 2239943 2240011 + ID1_N003 ID2_N003T0
SP12.3 XE 2240077 2241254 + ID1_N003 ... (12 Replies)
I am trying to get a simple min/max script to work with the below input. Note the special character (">") within it.
Script
awk 'BEGIN{max=0}{if(($1)>max) max=($1)}END {print max}'
awk 'BEGIN{min=0}{if(($2)<min) min=($2)}END {print min}'
Input
-122.2840 42.0009
-119.9950 ... (7 Replies)