Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!sdrc!thor!scjones
From: scjones@thor.UUCP (Larry Jones)
Newsgroups: comp.lang.c
Subject: Re: Assinging values to type float
Message-ID: <153@thor.UUCP>
Date: 4 Sep 90 14:17:13 GMT
References: <90240.003415RHMCSUPV@MIAMIU.BITNET> <11583@crdgw1.crd.ge.com>
Organization: SDRC, Cincinnati
Lines: 21

In article <11583@crdgw1.crd.ge.com>, volpe@underdog.crd.ge.com (Christopher R Volpe) writes:
> This raises a question I've been wondering about for a while: When
> we say that a float (or char) gets converted to a double (or int) in
> an expression, what exactly constitutes an expression? Is a single
> value on the RHS of an assignment operator an "expression" for
> conversion purposes? Or is at least one operator required? If
> I do a "f1=f2", does it first convert f2 to double and then back 
> to float in order to do the assignment? How about "c1=c2" for chars?       

An "expression" is defined by the C grammar.  No operators are
required, "i" is an expression as is "f1=f2" (note that "=" is
the assignment >operator< in C).  In fact "f1=f2" should cause
f2 to be widened to double and then narrowed back to float.
Fortunately, even very dump compilers are smart enough to
optimize out the spurious widening and narrowing operations.
----
Larry Jones                         UUCP: uunet!sdrc!thor!scjones
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