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From: beard@ux1.lbl.gov (Patrick C Beard)
Newsgroups: comp.lang.c++
Subject: Re: Resolving an Overloaded Function Call
Keywords: overloading
Message-ID: <5545@helios.ee.lbl.gov>
Date: 3 May 90 17:34:59 GMT
References: <35925@think.Think.COM> <1990May3.030546.1885@agate.berkeley.edu>
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Reply-To: beard@ux1.lbl.gov (Patrick C Beard)
Organization: Lawrence Berkeley Laboratory, Berkeley
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X-Local-Date: 3 May 90 10:34:59 PDT

In article <1990May3.030546.1885@agate.berkeley.edu> c60c-2ca@e260-2a (Andrew Choi) writes:
#In article <35925@think.Think.COM> simons@think.com (Joshua Simons) writes:
#>
#>	I have a question about resolving overloaded function calls in
#>C++. In Lippman's book, 'The C++ Primer' there is an example on page 155
#>which says that the following function call:
#>
#>	print( 'a' ) ;
#>
#>exactly matches the overloading:
#>
#>	extern void print( char ) ;
#>
#>	Is this an error? I don't know C++, but in C the type of the
#>expression 'a' is 'int' not char so I don't see how this could be an
#>exact match. Is C++ different from C in this regard?
#
#	No, this is not an error.  In C++ version 2.0, a character
#literal/variable is considered to match perfectly with a formal
#parameter of type `char'.  It will only considered to match
#an `int' (and higher derived type) if a perfect match is not found.

To clarify the point, yes, C++ is different from C in this regard.  A character
literal is of type "char".  This was introduced for exactly this reason:  to
permit more precise argument type matching for the resolution of which 
overloaded function to call.

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-  Patrick Beard, Macintosh Programmer                        (beard@lbl.gov) -
-  Berkeley Systems, Inc.  ".......<dead air>.......Good day!" - Paul Harvey  -
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