Php-mysql Course

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
Which meta tag provides a short description of the page?
<meta content="..."> <meta description="..."> <meta http-equiv="...">
<meta name="description" content="70-160 characters that describes the content of the page" />
Which CSS property is used to stop the wrapping effect of the "float"?
clear text-align position
#some_id {
  clear: both;
}
Click on the method which gets an array with all the elements in the document that have a specified tag name.
getElementsByName() getElementById() getElementsByTagName()
var divs = document.getElementsByTagName("div");
var nr_divs = divs.length;
alert(nr_divs);
Indicate the PHP function which returns the number of elements in array.
is_[) count() strlen()
$arr =[7, 8, "abc", 10);
$nri = count($arr);
echo $nri;        // 4
Recursive Functions in PHP

Last accessed pages

  1. Add data from form in text file in JSON format (14619)
  2. SHA256 Encrypt hash in JavaScript (23809)
  3. setTimeout and this with bind() method in JavaScript class (3511)
  4. Download AJAX resources (153)
  5. Node.js Move and Copy Directory (15377)

Popular pages this month

  1. PHP Unzipper - Extract Zip, Rar Archives (475)
  2. Courses Web: PHP-MySQL JavaScript Node.js Ajax HTML CSS (455)
  3. SHA256 Encrypt hash in JavaScript (392)
  4. Read Excel file data in PHP - PhpExcelReader (348)
  5. Create simple Website with PHP (331)