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From: estdwha@warwick.ac.uk (CrisP)
Newsgroups: comp.sys.amiga.misc
Subject: Re: Object Oriented Programming
Message-ID: <1991Jan30.144546.10478@warwick.ac.uk>
Date: 30 Jan 91 14:45:46 GMT
References: <42954@nigel.ee.udel.edu> <749@caslon.cs.arizona.edu>
Sender: news@warwick.ac.uk (Network news)
Organization: Computing Services, Warwick University, UK
Lines: 52

In article <749@caslon.cs.arizona.edu> dave@cs.arizona.edu (Dave P. Schaumann) writes:
>In article <42954@nigel.ee.udel.edu> NJ_GOKEM%FANDM.BITNET@pucc.princeton.edu writes:
>|Hi out there,
>|
>|I am taking a seminar in Object Oriented Programming, and now the class
>|seems to believe that OOP is slower than Procedure-programming.
>|An article in Byte in 86 argues that it could be 50 % slower.
>|
>|I want to help this belief out of the world!
>| Does anyone have any comments?
>|Or is C++, and Smalltalk slower than regular C ???
>
>Yes, it is true.  Object oriented programming languages are generally slower
>than more traditional languages.  Additionally, many OOPL (like Smalltalk)
>are traditionally interpreted (slowing them down more).
>
>|The basic argument is that the computer would spend too much time trying to
>|find the right "METHOD" in the tree of inherited "METHODS", since OBJECTS
>|inherit a lot of "METHODS". Is this TRUE?
>
>The designers of C++ took the course of getting OO functionality with the
>minimum amound of cost at execution time.  They got it down to the cost
>of an extra indirection for every function call.  Eg., a call like
>bar->foo() in C++ translates to something like (*bar->foo)() in actuality.
>(modulo the hidden 'self' parameter, of course).

Not quite. bar->foo() in C++ translates to something like foo(bar) in C.
Actualy it doesn't use foo but a symbol that is "unique" to a call the foo
in that perticular class. ( Whatever class bar may be. ) So in theory a C++
program should execute just as fast as a C program. The style of object
oriented programming sacrifices some executing speed for development speed.
In reality the C++ compilers arn't as good as the C compilers alough there
is no reson why the can't be. I don't know how the C++ to C interpreters
produce less efficent code than code written C in an similar style, but
CC-2.1 on a Sun3 seems to do it.

>
>The moral of the story is There Aint No Such Thing As A Free Lunch.
>(say, that sounds familiar...)
>
>|Nils Gokemeijer
>|(NJ_GOKEMEIJE@FANDM.bitnet)
>
>
>Dave Schaumann		|  And then -- what then?  Then, future...
>dave@cs.arizona.edu	|  		-Weather Report

~CrisP.
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crisp@uk.ac.warwick.cs | estdwha@uk.ac.warwick.cu
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