Path: utzoo!mnetor!uunet!husc6!purdue!gatech!emory!platt
From: platt@emory.uucp (Dan Platt)
Newsgroups: comp.lang.fortran
Subject: Re: Recursion
Message-ID: <2787@emory.uucp>
Date: 26 Mar 88 23:26:34 GMT
References: <7975@agate.BERKELEY.EDU> <533@a.UUCP>
Reply-To: platt@emory.UUCP (Dan Platt)
Distribution: na
Organization: Emory University
Lines: 17

Following a bunch of stuff about recursion being permitted, we have:


In article <533@a.UUCP> jlg@a.UUCP (Jim Giles) writes:
>...  The question I asked was: "Why is the keyword RECURSIVE
>necessary?"

Recursion requires variables to be passed by value (in general) rather than
by address.  If a variable is passed by address, then changing the variable
in the subroutine changes the value in the called routine as well.  If the
value is placed "on the stack" so that the subroutine works with the values
in a separate variable space (a new one for each call - and each level of
recursion), then changing the variable won't affect its value in the calling
routine.  In other words, the calling routine will remember the value rather
than having it changed with each recursive call....

Dan Platt