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From: ogud@SDAG.CS.UMD.EDU (Olafur Gudmundsson)
Newsgroups: comp.os.vms
Subject: Re:  Language question
Message-ID: <8705221905.AA01082@sdag.cs.umd.edu>
Date: Fri, 22-May-87 15:05:36 EDT
Article-I.D.: sdag.8705221905.AA01082
Posted: Fri May 22 15:05:36 1987
Date-Received: Sat, 23-May-87 18:49:37 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 41

>I have a question concerning a problem that Fortran does not handle well.
>I would like to write a subroutine that gets as arguments the following:
>
>            (1)  An array
>            (2)  The type of array (byte, integer*2, integer*4, real*4, etc.)
>
>In the subroutine I want to write to a file (or otherwise manipulate) data
>from the passed array.  Fortran has an obvious problem with data typing.
>
The simple solution to your problem is to use equivalence statements
this way there is no overhead because of copying.
The only overhead is that you will have to use IF statments to pick the
right data to work with

Example :
	subroutine foo( arr, typ)

	int arr( *)   , typ 
	real r4( 1)
	integer*2 i2(1)
	byte	c1(1)
	eqivalence (arr(1), r4(1) , i2(1) ,  c1(1))

c    and in the subroutine you do
	if( typ.eq. INT) then

	else if( typ .eq. REA4) then

	...

	endif

	and so on 

----------------------------------------------------------------------------
Spelling mistakes make life more colorful
____________________________________________________________________________
Olafur Gudmundsson  Dept. of Computer Science University of Maryland
ARPA: ogud@sdag.cs.umd.edu
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