[Lazarus] procedure FloatToDecimal

Héctor Fiandor Rosario hfiandor at infomed.sld.cu
Mon Sep 1 18:52:51 CEST 2008


diar Mr. Reenen Laurie:

thanks very much for your answer.

really, I think that my problem was in the TFloatRec. I see  that you declare as var. I will try your suggestions.

yours,

Ing. Héctor F. Fiandor
hfiandor at infomed.sld.cu
  ----- Original Message ----- 
  From: Reenen Laurie 
  To: General mailing list 
  Sent: Monday, September 01, 2008 1:29 AM
  Subject: Re: [Lazarus] procedure FloatToDecimal


  Procedure FloatToDecimal(Out Result: TFloatRec; Value: Extended; Precision, Decimals : integer);

  The Precision, and Decimals work together to ensure the rounding etc. 

  So lets say you want to have float to decimal, and have 5 "digits"...  And you do it on a value of 2 then the result will be
  2.00000

  If you only want a precision 2 but want decimals 5, and run it for pi, you will get
  3.14000

  So general rule is to have your precision higher than your digits, and you'll have good "rounding".

  Hmmm... My test program shows some funnies:

  procedure TForm1.FormDblClick ( Sender : TObject ) ;
  var t : TFloatRec; 
  begin
    FloatToDecimal(t,pi,5,3);
    ShowMessage(inttostr(t.Exponent)+'.'+t.Digits);
  end; 

  Shows 3.1432 -- not 3.143 as expected...

  FloatToDecimal(t,pi,2,6);
  Showed, 3.14

  (not 3.140000) as I expected...




  On Sat, Aug 30, 2008 at 4:19 AM, Héctor Fiandor Rosario <hfiandor at infomed.sld.cu> wrote:

    Dear sirs:

    I need to convert a Float to a number with two decimal places in a Lazarus
    Project for Windows..

    I am thinking to use the following procedure:

    Procedure FloatToDecimal(Out Result: TFloatRec; Value: Extended; Precision, Decimals : integer);

    begin
      FloatToDecimal(Result,Value,fvExtended,Precision,Decimals);
    end;

    but I dont know what to write in some of the arguments.

    Thanks in advance for your help,

    yours truly,

    Ing. Héctor F. Fiandor
    hfiandor at infomed.sld.cu

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