Recursive Functions are functions that auto-call themself. Generally, a recursive function returns a value that are passed as argument, so the value is passed from an auto-call to the other, until it is returned.
Recursive functions are very useful in equations with factorial numbers and some operatios with multi-dimensional array.
Factorials are written like 6! and this means: 6 * 5 * 4 * 3 * 2 * 1. So 6! is 4320 and 4! is 24.
In the fallowing example we have a recursive function that finds the factorial of a number "$nr" (here 8).

<?php
// this function auto-calls itself (decrementing $nr) until $nr is 0
function factorial($nr) {
  if($nr > 0) $re = $nr * factorial($nr-1);
  else if($nr == 0) $re = 1;

  return $re;
}

echo '8 factorial is: '. factorial(8);        // 8 factorial is: 45360
?>

- To see another example, visit this page: Get all the unique numbers from two-dimensional array.

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Click on the tag that creates an ordered list
<ul> <tr> <ol>
<ol>
  <li>List-1</li>
  <li>List-2</li>
</ol>
Which selector represents the ID of an element in CSS
.name #name name
#id {
  color: #0110fb;
}
What statement creates an object in JavaScript?
{} [] new Date()
var obj = {"site": "CoursesWeb.net", "pr": 5};
alert(obj.site);
Indicate the instruction used to evaluate if a condiition is True or False
else if() switch()
$var = 8;
if($var == 8) echo $var;
Recursive Functions in PHP

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