Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!wuarchive!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: comp.lang.c++
Subject: Re: const
Message-ID: <142@tdatirv.UUCP>
Date: 5 Sep 90 15:59:11 GMT
References: <10863@cadillac.CAD.MCC.COM>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 40

In article <10863@cadillac.CAD.MCC.COM> vaughan@puma.cad.mcc.com (Paul Vaughan) writes:
>Consider the following function
 
>const char* substring(const char* string, const char* sub) 
>// substring searches for the first occurence of sub in string and
>//returns a pointer to it or 0 if none is found.
>{ ....}
>
>If I'm working on a const char* (and, therefore, don't plan on changing
>any part of it) this works just fine.  However, if I'm working on a
>char* and was planning to change part of it and was using substring to
>find that part, this will cause a problem because substring returns a
>const. ...
 
>I can't declare substring as 
 
>char* substring(const char* string, const char* sub) 
 
>because it is returning a pointer to part of the string that is passed
>in.  I would declare it
>
>char* substring(char* string, const char* sub)
>
>but then I can't use it to deal with const char*'s, and, of course, I can't
>overload it based on the return type!

But I believe you *can* overload it on the type of the first argument based on
the presence/absence of 'const'.  In other words, declare it *both* the first
and the second way.  This will then call either the const or non-const version
depending on whether the first argument is a const string or not.
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uunet!tdatirv!sarima				(Stanley Friesen)
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