PHP Class Exercises : Calculate the factorial of an integer

Last update on May 30 2022 11:48:24 (UTC/GMT +8 hours)

PHP class: Exercise-3 with Solution

Write a PHP class that calculates the factorial of an integer.

Sample Solution:

PHP Code:

<?php
class factorial_of_a_number
{
  protected $_n;
  public function __construct($n)
   {
     if (!is_int($n))
	   {
	      throw new InvalidArgumentException('Not a number or missing argument');
       }
    $this->_n = $n;
	}
  public function result()
    {
     $factorial = 1;
     for ($i = 1; $i <= $this->_n; $i++)
	  {
	    $factorial *= $i;
      }
	   return $factorial;
	 }
 }

$newfactorial = New factorial_of_a_number(5);
echo $newfactorial->result();
?>

Sample Output:

Flowchart :

PHP Code Editor:

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Previous: Write a simple PHP class which displays an introductory message like "Hello All, I am Scott", where "Scott" is an argument value of the method within the class.
Next: Write a PHP class that sorts an ordered integer array with the help of sort() function.

What is the difficulty level of this exercise?

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC