Factorial using PHP

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.
For example, 5! = 5 x 4 x 3 x 2 x 1 = 120
The value of 0! is 1, according to the convention for an empty product.
To know more about factorial, click here.

"My version of non-integer factorial"

<?php // For example, 5! = 5 x 4 x 3 x 2 x 1 = 120 $f = $temp1 = $temp2 = 5; while ( --$temp2 > 0) {   $temp1 *= $temp2; } echo $f . '! = ' . (($f>=0) ? (($f==0) ? 1 : $temp1) : ''); // The output is: 5! = 120 ?>

Explaination

1. Equate integer 5 to the three different variables $f, $temp1 and $temp2

$f = $temp1 = $temp2 = 5;

2. Condition of while loop. At the first place the server will pre-decrement ($temp2 = $temp2 - 1) the variable $temp2 before it checks if $temp2 is greater than 0 ($temp2 > 0).

while ( --$temp2 > 0) { // statement here }

3. While the condition is true $temp1 = $temp1 * $temp2

$temp1 *= $temp2;

4. After the loop,it will print the $f and concatenate to string '! = ' then concatenate to ternary result. If (($f>0) ? TRUE : FALSE), if it is TRUE, it will proceed to 2nd ternary which is (($f==0) ? 1 : $temp1 ), if $f==0, the result is 1 else simply $temp1. If the 1st ternary turns to FALSE, it will concatenate to empty string.

echo $f . '! = ' . (($f>=0) ? (($f==0) ? 1 : $temp1) : '');

And that is my version of non-integer factorial.

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