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From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: typedef-ing an array
Message-ID: <25585@mimsy.umd.edu>
Date: 20 Jul 90 03:07:29 GMT
References: <78627@srcsip.UUCP> <78633@srcsip.UUCP> <1990Jul3.231408.14315@everexn.uucp>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 36

Although I already followed up to the original question, I should
correct something here:

In article <1990Jul3.231408.14315@everexn.uucp> roger@everexn.uucp
(Roger House) writes:
>... The string "Silly old me" is of type "pointer to char".

The type of a string constant is `array N of char', where N is one more
than the number of characters in the string% (the extra one is for the
final '\0' character).  In this case the type is `array 13 of char'.  The
string was, however, in a value context and as such undergoes the
usual transformation:

    In any value context, an object of type `array N of T' becomes a
    value of type `pointer to T' whose value is the address of the
    first (0th) element of the array.

This rule is extremely important.  Like the rule `a*b = b*a', it must
simply be memorised as a Fact Of C.  Given that and the rules of pointer
arithmetic and indirection, you can derive a consistent method for
dealing with arrays and pointers.
-----
% I am intentionally ignoring multibyte strings here, as they mainly
  serve to confuse the issue.

>In C you cannot assign a value to an array by using the assignment
>operator "=".

This is correct: an array is not a modifiable lvalue (i.e., it may not
be assigned to).  Note that an initialization (e.g., char x = 'f';)
is not an assignment (under ANSI X3.159-1989 at least; in Classic C
automatic initializers were semantically identical to assignments,
but under New C aggregates are permitted here).
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris