Re: Leading zeros with Int_IO.Put()? Or another package?

[johnherro@aol.com (John Herro)]

baldwin@netcom.com (J.D. Baldwin) wrote:
> if (MINUTE <= 9) then
>    Int_IO.Put(0, 0);
> end if;
> Int_IO.Put(MINUTE,0);
> ... is there a better way to pad out integers
> with leading zeros?

I don't know if this way is "better," but here's how I force leading zeros
when I know the number is never too large for the desired width and the
number is never negative.  (In this example, Minute is never more than two
digits and never negative).  Let's call the desired width W.  Add the
constant 10**W, take the 'Image, which will always have exactly W+2
characters, and select the last W characters of the result.  For example,
if Minute = 4 and is of type Integer, then Integer'Image(104) is " 104"
and the last two characters are "04".  In your code, you COULD replace
four lines with

Ada.Text_IO.Put(Integer'Image(100 + Minute)(3 .. 4));

This technique works only when W is small enough that 10**W plus the
largest number you're going to handle doesn't overflow.  For example, if
the number you're outputting is an Integer and Integer'Last is
2_147_483_647 (ten digits), then W can be at most nine to avoid overflow. 
Within that limit, this technique can force multiple leading zeros to any
desired width.

Whether this way of forcing leading zeros is "better" is certainly
debatable.  All I can say for certain is that it's fewer lines.

- John Herro
Software Innovations Technology
http://members.aol.com/AdaTutor
ftp://members.aol.com/AdaTutor
-----
ANSWER: "Close cover before striking."
QUESTION: What did the labor union leader say to the sewer workers?