Article View: comp.lang.misc
Article #910Re: Relationship between C and C++
From: Preston Briggs
Date: Tue, 20 Mar 1990 22:17
Date: Tue, 20 Mar 1990 22:17
36 lines
1296 bytes
1296 bytes
In article <5200048@m.cs.uiuc.edu> robison@m.cs.uiuc.edu writes:
>Can anyone clue me as to the basis for pointer paranoia?
Just because I'm paranoid doesn't mean I'm stoopid.
Let's do some pointer arithmetic.
First we need some declarations:
typedef struct {
int i; /* say 4 bytes */
char c;
} Node, *Nodes;
Nodes x, y;
int i, j;
And then some code (assume with me that things are initialized):
x = y + i;
This means assign the sum of y and i*5. Not too bad, 1 shift and 3 adds.
Let's do some more:
j = x - y;
Hmmm. A subtract and a DIVISION by 5!?
This stuff is great! Plus costs 4 times what it should and minus
becomes worse than division. *And* it makes my code obscure to
myself and others, not to mention hard to optimize. Such a deal.
--
Preston Briggs looking for the great leap forward
preston@titan.rice.edu
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rice!titan!preston From: preston@titan.rice.edu (Preston Briggs) Newsgroups: comp.lang.misc Subject: Re: Relationship between C and C++ Message-ID: <5919@brazos.Rice.edu> Date: 20 Mar 90 22:17:31 GMT References: <8432@hubcap.clemson.edu> <5200048@m.cs.uiuc.edu> Sender: root@rice.edu Organization: Rice University, Houston Lines: 36