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From: damm@rimfaxe.diku.dk (Kristian Damm Jensen)
Newsgroups: comp.lang.pascal
Subject: Re: complex numbers
Message-ID: <4658@freja.diku.dk>
Date: 16 Jul 89 10:23:23 GMT
References: <2751@ohstpy.mps.ohio-state.edu> <2360@pur-phy>
Sender: news@freja.diku.dk
Lines: 36

hal@pur-phy (Hal Chambers) writes:

>In article <2751@ohstpy.mps.ohio-state.edu> heff@ohstpy.mps.ohio-state.edu writes:
>>. . . to write equations in source code such as
>>                     a =: b + c;
>>                     a := (b+c)/(d+e);
>>as can be done in fortran.  For that matter, are there any languages beside
>>fortran which allow easy computation of complex numbers?

>Although Pascal (and Modula-2, etc.) allows the definition of a Complex
>type,  there is no way for the programmer to define the operators
>other than as explicit procedure calls (functions can't return a
>structured type).

No, but you can return a pointer to a structured type. 
In fact I once received a whole packages of about 10K to do 
complex-arithmetic programmed that way.

>So the examples above would appear as something like:
>    >   a =: b + c;
>		cadd(a, b,c);
or if you use functions as described

	a := cadd (b, c);
>    >   a := (b+c)/(d+e);
>		cadd(c1, b,c);
>		cadd(c2, d,e);
>		cdiv(a, c1,c2);
>Ugly!!!!
	a := cdiv (cadd (b, c), cadd (d, e))

with a, b, c, d and e being pointers to the records containing the complex 
numbers. Not to bad if yoy don't dislike a lisp-like programming style.

-------------------------------------------------------------------------
Kristian Damm Jensen (damm@freja.diku.dk)