Well, you can't do this to the "number", since the number itself
doesn't care about things like leading zeros. Just treat it as a
string...

string sVal = value.ToString(); // or whatever
if((sVal.Length % 2) == 1) { // odd length
 sVal = "0" + sVal; // left-pad with zero
}

That do?

Marc

What if you already have a four-digit number?  Should numbers with an even  
count of digits be left alone?

Are you sure this isn't a homework assignment?  Sure doesn't sound like  
anything you'd find in non-academic code.

Anyway, the first step is to understand that until you've converted a  
number to a string, based on some particular number base (base 10,  
apparently in your case) there is no such idea as "number of digits".  
Once you figure that out, then it's a simple matter to count the digits  
and prepend the character '0' when needed.

Pete

string myNum = 123.ToString();
string fubar = ((myNum.Length % 2) == 1) ? "0" + myNum : myNum;

Good luck with your assignment!!

Regards

John Timney (MVP)
http://www.johntimney.com
http://www.johntimney.com/blog

This seems to work (thought up and tested just now, but not fully tested):

int iNumber = 1234;
string sNumber = iNumber.ToString();

sNumber =
   sNumber.PadLeft(sNumber.Length + (sNumber.Length % 2), '0');

Console.WriteLine(sNumber);

for 1234 it reads:
1234

for 12345 it reads:
012345

for 123456 it reads:
123456

for 1234567 it reads:
01234567

HTH,
Mythran