PHP: Simple recursive function into iterative function

Question

I was going to do it in C but was confused, so I turned to PHP and was able to copy a recursive function to do this. I am converting an integer into a string with math. Here it is:

function intToString($myDecimal){
 if($myDecimal < 10) {
 return $myDecimal;
 }
 return intToString(($myDecimal / 10)) . ($myDecimal % 10);
}

I was able to convert a recursive factorial function before.. but with this I just have no clue.. My attempt is as follows:

function intToStringIter($myDecimal){
 $out = "";
 while($myDecimal > 10) {
 $myDecimal /= 10;
 $out .= $myDecimal;
 }
 $out .= $myDecimal % 10;
 return $out;
}

I think I am too tired to see the proper logic at the moment.. It returns 22 instead of 20, I cannot wrap my head around what is correct. Do you see what I am doing wrong?

• RobertPitt: Example of the usage please ?
• xPheRe: I can't find the point. Is this homework? Conversion between integer and strings isn't needed in PHP.
• John: @xPheRe, It was for an interview question a friend had asked about, he wasn't in the interview he just read about the question, I was helping him understand how to do it.

Answer 1

If you're looking for a conversion to string for big unsigned integers, the code is actually:

function intToString($myDecimal)
{
 return sprintf('%u', $myDecimal);
}

If you need to do it with iteration:

function intToString($myDecimal)
{
 $result = '';
 while ($myDecimal > 9) {
 $result = ($myDecimal % 10) . $result;
 $myDecimal /= 10;
 }
 return $myDecimal . $result;
}

UPDATE: My bad, digits were inserted in reversed order. Now it should work. Sorry, untested too.

• John: I was wanting to do it in C, which used no standard functions (so sprintf is out), your second example spits out "02" instead of "20", weird. I am really just helping somebody do this in C, I will stop wracking my mind and go to sleep. :)
• xPheRe: I updated my answer, you were right, it built the string in reverse order. Now it should work fine. I hope.
• John: Ah! After some sleep I understand this now, it works perfectly and applies to the problem I wanted to help somebody with. It should be simple to do in C now (with simple ASCII addition). Thank you

Answer 2

PHP is not very strict with variables. An integer will become an float if the situation likes it. In your code, $myDecimal /= 10 could make a float of $myDecimal. The following forces $myDecimal to stay an integer. Note: you should pass only integers, if you're passing 9.99, the output would still be 9.99 because 9.99 < 10.

function intToStringIter($myDecimal){
 $out = "";
 while($myDecimal >= 10) {
 $myDecimal = (int) ($myDecimal / 10);
 $out .= $myDecimal;
 }
 $out .= $myDecimal % 10;
 return $out;
}