From:	"H.W. Stockman" <hwstock AT swcp DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: checking types
Date:	Sat, 13 Sep 1997 16:14:31 -0600
Organization:	Lentil Sorbet, Inc.
Lines:	21
Message-ID:	<341B1047.3EA9@swcp.com>
References:	<341B0CE1 DOT 29B0 AT sprintmail DOT com>
Reply-To:	hwstock AT swcp DOT com
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To:	djgpp AT delorie DOT com
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anfamily AT sprintmail DOT com wrote:
> 
> How would you check a variable to make sure it's a certain data type you
> want it to be?  I have a small prog, that needs this.  It prompts you
> for an integer, but you can enter other types.  If you enter other
> types, if really screws up the prog.  I'm using a scanf to get that
> value for a variable, but after that, I want to check to make sure the
> value in that variable is a integer.  If it's not, it would prompt the
> user again.  How would I do that?

The value read by scanf as %d will end up being an integer --
it just may not be an integer that you want.  You can always
read it into a temporary itemp, then check that itemp is within
the desired limits.

Alternatively, you can read in a string, then either extract
the value with sscanf, or check for warning signs in the tokens--
like character ascii values that are not in >='0' and <='9'.
I used scansets before to restrict the characters read in, but
it has been so long, I don't know if these ever made it into
the ansi standard.

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