Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!ncar!tank!oddjob!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.fortran
Subject: Re: An array by any other name. . .
Message-ID: <13587@mimsy.UUCP>
Date: 16 Sep 88 11:16:26 GMT
References: <994@amelia.nas.nasa.gov> <3641@lanl.gov>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 41

In article <3641@lanl.gov> jlg@lanl.gov (Jim Giles) writes:
>x[i] and *(x+i) are semantically equivalent in C.

(good so far)

>I don't _want_ them to be.

(Well, there is no accounting for taste.)

>...  With the pointer, I _don't_ want the language to apply any
>constraints on where it can point;

None at all?  C requires that it point to some integer.

>with the array I want array bounds checking - that's two different
>semantics folks!!!

Actually not.  You can buy a C compiler (from Sabre) that will
do bounds checking.  (It does the checking on pointers, too,
including on pointers to regions allocated by malloc.)

>Furthermore, in C x[i][j] is _supposed_ to be semantically equivalent
>to *(*(x+j)+i).  Statically allocated 2-d arrays aren't implemented
>this way!

Ah, but they are.

>In order to get a dynamically allocated to behave semantically like
>a statically allocated one I have to use a _different_ declaration
>syntax.  

True, but only with a qualifier.  This applies to dynamically
allocated, dynamically *sized* arrays, which simply do not exist in C.
(Neither do they exist in FORTRAN.)  Also, the C language does not have
`conformant' (dynamically sized, who-cares-how allocated) arrays, which
makes dealing with multidimensional array arguments unnecessarily
painful.  *This* is the only thing FORTRAN has here that C does not.
(It *is* a rather large thing.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris