As you already knew that how factorial works in mathamatics if not then follow this link Click Here. We are going to write the code that will take a number as input and show the factorial of it. I’ts very simple. Follow the code below.
Code Example:
<form method="post">
<input type="number" name="txt" value="<?php echo $_POST['txt']; ?>" /><br />
<input type="submit" name="sbt" />
</form>
<?php
if (isset($_POST['sbt']))
{
$num = $_POST['txt'];
$fac = 1;
for ($num ; $num > 0 ; $num--){
$fac *= $num;
}
echo "Factorial is ".$fac;
}
?>
Result:
