Count digits after point

[Aphton]

@DelphiProgrammer:
Nope!

Delphi-Quellcode:

var
  x: Single;

begin
  x := 2.048;
  writeln(x);
  writeln((length(floattostr(x)) - pos('.',floattostr(x))-1));
  readln;
end.

Output

Code:

 2.04800009727478E+0000
15

[WojTec]

I thought about strings too, but (1) it's lame and (2) see @Aphton's post.

There is no math solution?

[Aphton]

This might be a problem that can be solved in another way.
You want to find out the number of fraction-digits.
Why?
Maybe the root problem you are trying to solve can be solved in another way! Maybe you dont even need to find out the digitcount!

[mkinzler]

Why you need the number of digits? perhaps there is a better way to achieve your aim.

[Aphton]

@mkinzler: xDD

[WojTec]

So, reason is not important. Important is problem.
But if you want to know: (1) result is required for further computation purposes and (2) for formating.

[mkinzler]

For (1) because the system iminent computation error the consumption more digits are better doesn't seem right to me.
For (2) I'd prefer to restrict the digits to dispay to a fixed count

[swkevin08]

as the others have said, it has something to do with the approach.
but look at this. maybe it will help you!

ps: doenst work for all numbers! for example x,42300000000000000001

Edit: e was randomly generated

Code:

const
  e = 0.0000000001;

function CountDigitsAfterPoint(AValue: Extended): Byte;
var r: Extended;
begin
  Result := 0;
  r := Int(AValue);
  while ((Frac(AValue) <> 0) and ((AValue - r) > e)) do
  begin
    Inc(Result);
    AValue := AValue * 10;
    r := Int(AValue+e);
  end;
end;

[Furtbichler]

Zitat von WojTec:

So, reason is not important. Important is problem.
But if you want to know: (1) result is required for further computation purposes and (2) for formating.

The reason is always important, especially when people don't seem to exactly know what they are talking about.

Showing the number of decimals is definitely not something to please the eye. It is showing the accuracy of your value, so a value of, say, 100 (metres) measured up to a mm is correctly shown as "100,000 m" whereas the same value with an accuracy of 1m is shown as "100m".