Re: Is this program OOP?

wij <wyniijj5@gmail.com> writes:

On Tue, 2024-12-10 at 17:04 +0100, David Brown wrote:
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On 10/12/2024 10:23, wij wrote:
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On Mon, 2024-12-09 at 22:15 -0800, Tim Rentsch wrote:
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wij <wyniijj5@gmail.com> writes:
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On Mon, 2024-12-09 at 09:35 -0800, Tim Rentsch wrote:
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wij <wyniijj5@gmail.com> writes:
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Because I said:  C++ is the best language to model general
problems.  So it is.
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Almost all are logical propositions.  Except those few
keywords, such programwon't be recognized as a C++ program,
instead of some kind of declarative language.
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Zebra puzzle is an interesting programing exercise because it
is not too easy and also not too difficult.
>
------------
/* Copyright is licensed by GNU LGPL, see file COPYING. by
I.J.Wang 2023
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Example of solving the zebra puzzle by using propositional logic.
Zebra Puzzle https://en.wikipedia.org/wiki/Zebra_Puzzle
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[...]
*/
#include <Wy.stdio.h>
#include <Sc/PropExpr.h>
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using namespace Wy;
using namespace Sc;
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[...]

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You're asking a question that cannot be answered because much
or most of the program is in the two include files, which are
not shown.
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As a general rule, when posting code there should be enough
posted so that readers can at least compile it.  In cases like
the program asked about here, what is posted should be enough
to both compile the program and run the generated executable.

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I thought nobody will be interested with the implement, and what
is shown should be enough for the moment.

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The point is that what was posted is not enough to answer the
question of the Subject: line.
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The Zebra Puzzle program has two version, a_puzzle_21.cpp (has
shown) takes too long to complete.  a_puzzle_2.cpp (736 lines,
too long to post, I thought) is the realistic one written in way
I feel just solving the prolem is enough.

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I wrote a program in prolog to solve this puzzle.  The entire
program is 60 lines long, including 13 blank lines.  It finds the
solution in 0.03 seconds.  The program doesn't do anything fancy;
it pretty much just gives the listed conditions in the form of
prolog rules, plus 20 lines to establish the structure of the
information that is being sought.

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Very dubious, show us what you say is true.

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Prolog is a language that is ideally suited to such problems.
Basically, you give the language a bunch of objects and facts and
relations about those objects, then you ask it questions about
them.  It's at least 35 years since I tried Prolog one afternoon,
and that's exactly the kind of task I played with (though a bit
smaller).

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I know a bit of prolog,lisp (in DOS era).  Strongly suspicious what
Tim says.
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This is not a big problem in any language.  It's 5 characteristics
for each of 5 houses - that's 3125 possibilities.  Make a big array
of booleans, initialised to true.  Run through the array and kill
any combination that is contrary to one of the facts.  It might
have been a worthy benchmark in 1962 but it should not be
challenging to solve with modern machines.  (Of course it can still
inspire interesting solutions and ways to express code in different
languages.)

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Not that simple, try it to know (your eye may fool you, just like
with libwy).
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a_puzzle_2.cpp (736 lines) was a random try in normal C++
programming style.  I did not try to optimize it.  It took 3m22s.
a_puzzle_21.cpp has 178 lines, about 40 lines of comments, so
178-40=138 lines.  So, I have reason to doubt 60 lines of prolog
can do the job.  And most importantly, the number of 0.03 seconds
is too difficult to explain.  Prolog is not really a declarative
language, you need to provide 'algorithm' to 'compute' the answer.
So, there is reason why 'prolog' program can run faster.  But,
unless there is some built-in mechanism in modernprolog to solve
Zebra-puzzle-like problem, 60 lines of codes is dubious to me and
even so, 0.03 seconds remains highly dubious.

I'm wondering what it is you are dubious about.  Are you dubious

 (a) that I know how to use the 'wc' program to see how many
     lines there are in a file?

 (b) that I know how to use awk, and pipe the results into wc,
     to see how many blank lines there are in a file?

 (c) that I am capable of writing a prolog program that can be
     accepted and run by the swipl prolog interpreter?

 (d) that I know how to run a prolog program contained in a file,
     and look at the output it produces?

 (e) that I am capable of checking the output against the problem
     specification, to be sure the purported solution satisifies
     the conditions of the problem?

 (f) that I know how to use 'time' in a linux/unix shell, to see
     how long it took to run a program?

 (g) that I know how to interpret the output of 'time', and map
     it onto a time as measured by a regular time-keeping device
     such as a stopwatch?

Or is that you just think I'm a liar?

Incidentally I cleaned up the program a bit, and now it is only 50
lines long, including 13 blank lines.  It doesn't run any faster
than it did before;  still taking about 0.03 seconds of user time,
and about 0.04 seconds real time (that includes the time taken by a
short shell script wrapper to prettify the output).