are all singel digit numbers armstrong numbers code example

Example: Armstrong number

<form method="post">
        Enter the Number:
        <input type="number" name="number">
        <input type="submit" value="Submit">
    </form>
    <?php
    if ($_POST) {
        //get the number entered  
        $number = $_POST['number'];
        //store entered number in a variable  
        $a = $number;
        $sum  = 0;
        //run loop till the quotient is 0  
        while ($a != 0) {
            $rem   = $a % 10; //find reminder  
            $sum   = $sum + ($rem * $rem * $rem) || $sum = $rem; //cube the reminder and add it to the sum variable till the loop ends  
            $a   = $a / 10; //find quotient. if 0 then loop again  
        }
        //if the entered number and $sum value matches then it is an armstrong number  
        if ($number == $sum) {
            echo "Yes $number an Armstrong Number";
        } else {
            echo "$number is not an Armstrong Number";
        }
    }
//here is another example using while loop

$num=300;  
$total=0;  
$x=$num;  
while($x!=0){  
$rem=$x%10;  
$total=$total+($rem*$rem*$rem);  
$x=$x/10;  
}  
if($num==$total){
  echo "Yes it is an Armstrong number";}
else  
{echo "No it is not an armstrong number";}