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PHP Math Exercises: Get random float numbers

PHP math: Exercise-10 with Solution

Write a PHP function to get random float numbers.

Pictorial Presentation:

PHP Math Exercises: Get random float numbers

Sample Solution:

PHP Code:

<?php
function rand_float($st_num=0,$end_num=1,$mul=1000000)
{
if ($st_num>$end_num) return false;
return mt_rand($st_num*$mul,$end_num*$mul)/$mul;
}
echo rand_float()."\n";
echo rand_float(0.6)."\n";
echo rand_float(0.5,0.6)."\n";
echo rand_float(0,20)."\n";
echo rand_float(0,3,2)."\n"; 
echo rand_float(0,2,20)."\n";
?>

Sample Output:

0.613314                                                    
0.886207                                                    
0.57955                                                     
17.570268                                                   
1.5                                                         
1.6

Flowchart :

Flowchart: Get random float numbers

PHP Code Editor:

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PHP: Tips of the Day

PHP represents "no value" with the null keyword. It's somewhat similar to the null pointer in C-language and to the NULL value in SQL.

Setting the variable to null:

Example:

$nullvar = null; // directly
function doSomething() {} // this function does not return anything
$nullvar = doSomething(); // so the null is assigned to $nullvar

Checking if the variable was set to null:

if (is_null($nullvar)) { /* variable is null */ }
if ($nullvar === null) { /* variable is null */ }

Null vs undefined variable

If the variable was not defined or was unset then any tests against the null will be successful but they will also generate a Notice: Undefined variable: nullvar:

$nullvar = null;
unset($nullvar);
if ($nullvar === null) { /* true but also a Notice is printed */ }
if (is_null($nullvar)) { /* true but also a Notice is printed */ }

Therefore undefined values must be checked with isset:

if (!isset($nullvar)) { /* variable is null or is not even defined */ }