PHP random number generator


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An example of using a (pseudo)random number generator
Author: Elena Machkasova elenam@morris.umn.edu
Last modified: 2/23/10
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Random number generator in php
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<h2>(Pseudo)random number generator in php</h2>
<p>
Function rand() gives a random integer between 0 and the largest possible
integer. If you give the function a range of random numbers you want, it
returns an integer in that range. For instance, rand(5, 15) returns
an integer between 5 and 15 (inclusive). The result has an equal
probability to be any number within the range (i.e. it's a uniform
distribution). A new number is generated every time you use the function.
</p>
<p>
The numbers are not really random, the function is actually deterministic.
That's why the correct name for such functions is "pseudo-random number
generator".
It uses the current system time (up to nanoseconds) as the "seed" so that
number sequences come out different every time.
</p>
<p>
<?php
// note that calling a function within a quoted string doesn't
// work. Use string concatenation (the dot) for a function call
print "rand() = ".rand()."<br />\n";

print "rand(1, 10) = ".rand(1, 10)."<br />\n";

print "Another call to rand(1, 10) = ".rand(1, 10)."<br />\n";
?>
</p>
<p>
You can store a random number in a variable:
</p>
<p>
<?php
$r = rand(2, 5);

print "\$r = $r <br />\n";
?>
</p>
<p>
You can store a random number in a variable:
</p>
<p>
<?php
$r = rand(2, 5);

print "\$r = $r <br />\n";
?>
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http://csci1101sp10.morris.umn.edu/~elenam/1101_spring10/various/random.php


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