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Languages :: Delphi :: Undeclared Identifier (IsNan and LeftStr)
By: pipinana2002	Date: 19/06/2003 00:00:00	Points: 20	Status: Answered Quality : Excellent
Hi all.. I'm currently using Delphi 7. I would like to validate whether the data inputted in Edit is numeric. Hence, I tried to use IsNan function. But everytime I want to run the program, I always encounter an error: Undeclared Identifier: IsNan I also encounter the same problem when I want to take a few character of a string using LeftStr function. Anybody know how can I use these 2 functions? Do I have to declare it first or something.. coz I thought that it is declared by Dephi already.. Thanksss.. :)
By: ginsonic	Date: 19/06/2003 13:34:00		Type : Comment
LeftStr is declared into StrUtils unit. IsNan is declared into Math unit. Add to uses StrUtils,Math,....

By: pipinana2002	Date: 19/06/2003 13:53:00		Type : Comment
Hi ginsonic.. Can you give me an example of how to declare StrUtils and Math unit so I can use LeftStr and IsNan function? Thankss.. :)

By: VGR	Date: 20/06/2003 05:50:00		Type : Answer
in your program, you've : -a DPR file (the main source) with units referenced by a "Uses" clause -PAS units referencing each other by "Uses" clauses, either in implementation or in interface sections Choose the unit or source file where IsNan and LeftStr are used ; in implementation (probably), amend or add the "Uses" clause following the line "implementation" so that it includes : Uses SysUtils, Math;

By: pipinana2002	Date: 20/06/2003 18:25:00		Type : Comment
Hi.. I have tried the solution from VGR, but now I got this error when I want to run: If IsNan(Edit1.Text) Then ...... There is no overloaded version of 'IsNan' that can be called with this arguments Can you suggest what's the problem with this line? Thanks so muchh..

By: VGR	Date: 20/06/2003 18:36:00		Type : Comment
of course. IsNan (is Not A Number, x87 stuff here) is supposed to receive A NUMBER, not a string as Edit1.Text... Just do : If IsNan(StrToInt(Edit1.Text)) Then or use Val(), as usual

By: andrewjb	Date: 20/06/2003 21:27:00		Type : Comment
That's not going to work... the StrToInt will raise an exception. You don't want IsNan. Just do: try SrtToInt( Edit1.Text ) except ; /// It wasn't' a number - do whatever you want here end; And note that you'll get an exception when running in the IDE anyway - just hit F9 and it'll be trapped correctly.

By: ginsonic	Date: 20/06/2003 22:19:00		Type : Comment
uses ................., Math, StrUtils............ VGR, LeftStr is declared into StrUtils and not into SysUtils.

By: VGR	Date: 20/06/2003 22:23:00		Type : Comment
sorry 8-) do I have to flagellate myself after each typo found ? :D

By: ginsonic	Date: 20/06/2003 22:24:00		Type : Comment
function IsInt(const S: string): Boolean; var I, Err: Integer; begin Val(S, I, Err); Result := (Err = 0); end;

By: ginsonic	Date: 20/06/2003 22:26:00		Type : Comment
?!?!?! :P Nice speed in reply :)

By: pipinana2002	Date: 20/06/2003 22:59:00		Type : Comment
Hi again all.. Thanks so much for your helppp :):):) really2 very helpful for a beginner like me :D I finally resolved this problem.. using the solutions from VGR and andrewjb.. thanks sooo muchhh.. :)

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