But that's what my problem is. I don't know how many places after the
decimal.
The more I think about this, the more I realize that the only way for my
function to work is to know how many decimal places to the right I am
expected to format. This will have to be passed to my function from the
calling one.
Thanks for your insight,
Dave
Mike Walters <[EMAIL PROTECTED]> wrote in message news:41288@palm-dev-forum...
>
> If "%f" with no modifiers is passed to a standard sprintf function, it
> places 6 digits after the decimal point. So the values that sprintf
> produced for me were (using Unix):
>
> 12.345000
> 123.400002
> 1234.560059
> 1234.500000
> 12345.000000
>
> Some rounding errors were also introduced.
>
> I had a case about a month ago where I needed to print numbers in floating
> point format, and did not want the scientific format that FlptFToA
produced.
> Maybe there is a better solution, but since I knew I wanted four digits
> after the decimal, I did the following:
> - multiply the float by 10,000 (moves decimal place 4 places to right)
> - typecast the value to a long int
> - for each digit of the resulting integer
> - pick off last digit using a mod 10 (num %% 10)
> - add to string
> - after four digits added to string, insert a decimal point into
string
> - divide number by 10
> - reverse the string
>
> I know it is kind of brute force, but it works.
>
> Mike
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of David
> Leland
> Sent: Thursday, March 01, 2001 10:00 AM
> To: Palm Developer Forum
> Subject: Re: Determining number of decimal positions
>
>
> I was afraid that might be the case. So let me ask hypothetically, if the
> Palm OS supported the "%f" formatting modifier on the StrPrintF function
> (e.g. returnedString = StrPrintF("%f", floatValue);), what value would be
> placed into returnedString if the float values were:
> 12.3450
> 123.400
> 1234.56
> 1234.50
> 12345.00
>
> Dave
>
> Mike Walters <[EMAIL PROTECTED]> wrote in message
news:41279@palm-dev-forum...
> >
> > By "number of decimal places" do you mean the number before the decimal,
> the
> > number after, or both?
> >
> > 1) For the number before the decimal place: I don't know of a built-in
> > function, but you could use a small piece of code like the following to
> > count the number of places:
> >
> > int CountDigits (float your_val)
> > {
> > int count;
> >
> > count = 0;
> > while (your_val > 1.0)
> > {
> > count ++;
> > your_val /= 10.0;
> > }
> > return count;
> > }
> >
> > 2) For the number of digits after the decimal, the answer really can't
be
> > determined (do you count all of the trailing zeros, worry arount
floating
> > point rounding, etc). So the easiest thing to do is just select a value
> to
> > use in displaying your number, then truncate off any trailing zeros that
> you
> > don't want.
> >
> > 3) For the total number of digits, you could probably use a combination
of
> > the two methods above.
> >
> > Of course, for any kind of problem, you are going to find almost as many
> > solutions as you have responses. An without having the M&R book in
front
> of
> > me, I'm not sure the value that it is expecting to be passed.
> >
> > Hope this helps,
> >
> > Mike Walters
> > Rose Software
> >
> >
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]]On Behalf Of David
> > Leland
> > Sent: Thursday, March 01, 2001 9:28 AM
> > To: Palm Developer Forum
> > Subject: Determining number of decimal positions
> >
> >
> > I have a function that is being passed a float value. In my function, I
> > will be formatting that float value to a string (e.g. 1234.56 to
> 1,234.56)
> > and returning it. My problem is that I do not know the number of
decimal
> > places being passed. The float value could be 123.456 or it could be
> > 1234.56 or 12.3456. Is there a way I can determine how many decimal
> > positions that float value has?
> >
> > "Advanced Palm Programming" by Mann & Rischpater has an excellent
routine
> > for formatting a float value to a string but unfortunately, it expects
the
> > calling function to tell it how many decimal places to format. My App
is
> a
> > Plug-in to another Palm App so I don't have the luxury of knowing
upfront
> > how many decimal places the float value has.
> >
> > Thanks,
> > Dave
> >
> >
> >
> > --
> > For information on using the Palm Developer Forums, or to unsubscribe,
> > please see http://www.palmos.com/dev/tech/support/forums/
> >
> >
> >
>
>
>
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>
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