Re: how to check if a string variable contains a number or string?

["David C. Hoos" <david.c.hoos.sr@ada95.com>]

----- Original Message ----- 
From: "Stephen Leake" <stephen.a.leake.1@gsfc.nasa.gov>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: Monday, November 18, 2002 3:09 PM
Subject: Re: how to check if a string variable contains a number or string?


> mabes180@aol.com (Sarah Thomas) writes:
> 
> > I have an array of strings that I read in from a file. I want to check
> > if each element in the array is a string or if it is a number. is
> > there any predefined functions that would help do that? thanks
> 
> This sounds like a homework problem. If it is, please say so. We don't
> do homework for you, but we can give advice.
> 
> Since you are reading strings, obviously what you got is a string.
> It's possible that the string contains a valid number; I guess that is
> what you want to check.
> 
> Try reading the number from the string using Ada.Text_IO.*
It's cheaper and easier to use, say, Long_Float'Value, since 'Value for
real types will accept strings with or without a decimal point.

The downside is that Ada will disregard underscores embedded in
strings when attempting to convert a string to a numeric value.

If that's OK, then if calling Long_Float'Value doesn't raise
Constraint_Error, then the string is a valid decimal representation of a
number.

> 
> -- 
> -- Stephe
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