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From: martijn@and.nl (Martijn Bak)
Subject: Ada vs. C
Message-ID: <D385vK.GGq@and.nl>
Organization: AND Software B.V., Rotterdam
References: <3fnf28$s3f@Starbase.NeoSoft.COM>
 <3frqpg$re5@cronkite.seas.gwu.edu> <3g655n$q5k@theopolis.orl.mmc.com>
Date: Mon, 30 Jan 1995 15:33:19 GMT
Date: 1995-01-30T15:33:19+00:00
List-Id: <comp.lang.ada>

>It all falls out of the design of the language. Constructs like "+="
>provide no benifit other than to save typing within a single
>statement. Take the statement:
>
>  Principle = Principle + (Interest * Time)
>
>The "+=" operator is MADE for this statement, but its ONLY benifit is
>to save me 11 characters in my source file. 

Nope, in general this is _not_ true! The statements
	expr1 += expr2;
and
	expr1 = expr1 + expr2;
are _not_ the same. In the former, expr1 is evaluated only once, in the
latter expr1 is evaluated twice. This is not only a matter of execution
speed. It is especially important if expr1 has side-effects.

There is also a conceptual benefit for the += (if expr1 is very complex).
Compare
	a[i->j(q,b)] = a[i->j(q,b)] + 2;
and
	a[i->j(q,b)] += 2;

In the latter case, neither the writer nor the reader of this code need
to check whether a[i->j(q,b)] and a[i->j(q,b)] realy are the same.

Yep, I _am_ a C programmer.

-- 
-- Martijn Bak -- AND Software -- Westersingel 108, 3015 LD  Rotterdam --
-- tel: +31-10-4367100 -- fax: +31-10-4367110 -- email: martijn@and.nl --