Path: csiph.com!usenet.pasdenom.info!aioe.org!news.stack.nl!newsfeed.xs4all.nl!newsfeed3.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
MIME-Version: 1.0
In-Reply-To: <CAF3f0sQ_rsdKwaEOCmFHEeEwpVUaNUo-pOYgoqYA_F-k0CftcA@mail.gmail.com>
References: <CAF3f0sQ_rsdKwaEOCmFHEeEwpVUaNUo-pOYgoqYA_F-k0CftcA@mail.gmail.com>
From: Chris Kaynor <ckaynor@zindagigames.com>
Date: Thu, 18 Apr 2013 10:25:58 -0700
Subject: Re: equivalent to C pointer
To: "python-list@python.org" <python-list@python.org>
Content-Type: multipart/alternative; boundary=047d7bdca7c29685b304daa5e65a
Precedence: list
Newsgroups: comp.lang.python
Message-ID: <mailman.782.1366305989.3114.python-list@python.org>
Lines: 143
NNTP-Posting-Host: 2001:888:2000:d::a6
Xref: csiph.com comp.lang.python:43843

--047d7bdca7c29685b304daa5e65a
Content-Type: text/plain; charset=ISO-8859-1

While Python does not have pointers, Python functions are objects, and they
may be passed like any other object:

def F1(x):
    return x * x

def Trapeze(Fonc, left, right, step):
    ...code...
    Y1 = Fonc(X1)
    ...code...

def main():
   ...code...
   y = Trapeze(F1, -2.5, 3.2, 0.1)
   ...code...


Chris


On Thu, Apr 18, 2013 at 10:06 AM, abdelkader belahcene <abelahcene@gmail.com
> wrote:

> Hi everybody,
>
> I am new to python  and I am discovering it.
> I know C well,
> and want to know if python knows how to manage Pointers
> like pointer to function  here is a C example how to write it in python
> Intergration with trapeze method
>
> When we write Trapeze   ( at the compilation level) we don't know which
> functions
> Fonc  to handle.      Here for example we use  sin and a user defined  F1
> The program is attached too
>
> #include <stdio.h>
> #include <math.h>
>
> double F1 (double x){
>         return x*x;
> }
> double Trapeze(double Fonc(double ),
>                                 double left, double right, double step){
>   double X1, X0, Y0, Y1, Z = 0;
>   for(X0=left; X0 < right ; X0 = X0 + step) {
>     X1 = X0 + step;
>     Y1 = Fonc(X1);    Y0 = Fonc(X0);
>     Z  += (Y1 + Y0) * step * 0.5;
>   }
>    return Z;
> }
> int  main(){
>   double y;
>   y=Trapeze(sin, -2.5, 3.2, 0.1);
>   printf("\n\tValue for sin  is : \t %8.3lf ", y);
>   y=Trapeze(F1, 0, 3, 0.1);
>   printf("\n\tValue for F1 is : \t %8.3lf ", y);
>   return 0;
> }
> /**
>     Value for sin  is :         0.197
>     Value for F1 is :          9.005
>     */
> thanks a lot
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
>

--047d7bdca7c29685b304daa5e65a
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">While Python does not have pointers, Python functions are =
objects, and they may be passed like any other object:<div><br></div><div>d=
ef F1(x):</div><div style>=A0 =A0 return x * x</div><div style><br></div><d=
iv style>

def Trapeze(Fonc, left, right, step):</div><div style>=A0 =A0 ...code...</d=
iv><div style>=A0 =A0 Y1 =3D Fonc(X1)</div><div style>=A0 =A0 ...code...</d=
iv><div style><br></div><div style>def main():</div><div style>=A0 =A0...co=
de...</div><div style>

=A0 =A0y =3D Trapeze(F1, -2.5, 3.2, 0.1)</div><div style>=A0 =A0...code...<=
/div><div style><br></div></div><div class=3D"gmail_extra"><br clear=3D"all=
"><div>Chris</div>
<br><br><div class=3D"gmail_quote">On Thu, Apr 18, 2013 at 10:06 AM, abdelk=
ader belahcene <span dir=3D"ltr">&lt;<a href=3D"mailto:abelahcene@gmail.com=
" target=3D"_blank">abelahcene@gmail.com</a>&gt;</span> wrote:<br><blockquo=
te class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc so=
lid;padding-left:1ex">

<div dir=3D"ltr"><div><div><div><div><div><div><div>Hi everybody,=A0 <br><b=
r></div>I am new to python=A0 and I am discovering it.<br></div>I know C we=
ll,<br></div>and want to know if python knows how to manage Pointers<br></d=
iv>


like pointer to function=A0 here is a C example how to write it in python<b=
r></div><div>Intergration with trapeze method<br></div><div><br></div>When =
we write Trapeze =A0 ( at the compilation level) we don&#39;t know which fu=
nctions <br>


</div>Fonc=A0 to handle.=A0=A0=A0=A0=A0 Here for example we use=A0 sin and =
a user defined=A0 F1<br></div>The program is attached too<br><div><br><div>=
<div><div><div><div><div><div><div><div>#include &lt;stdio.h&gt;<br>#includ=
e &lt;math.h&gt;<br>


=A0<br>double F1 (double x){ <br>=A0=A0=A0 =A0=A0=A0 return x*x; <br>}<br>d=
ouble Trapeze(double Fonc(double ), <br>=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=
=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=A0=A0 double left, double right, d=
ouble step){<br>=A0 double X1, X0, Y0, Y1, Z =3D 0;=A0=A0=A0 <br>=A0 for(X0=
=3Dleft; X0 &lt; right ; X0 =3D X0 + step) {<br>


=A0=A0=A0 X1 =3D X0 + step;<br>=A0=A0=A0 Y1 =3D Fonc(X1);=A0=A0=A0 Y0 =3D F=
onc(X0);<br>=A0=A0=A0 Z=A0 +=3D (Y1 + Y0) * step * 0.5;<br>=A0 }<br>=A0=A0 =
return Z;<br>}<br>int=A0 main(){ <br>=A0 double y;<br>=A0 y=3DTrapeze(sin, =
-2.5, 3.2, 0.1);<br>=A0 printf(&quot;\n\tValue for sin=A0 is : \t %8.3lf &q=
uot;, y);<br>


=A0 y=3DTrapeze(F1, 0, 3, 0.1);<br>=A0 printf(&quot;\n\tValue for F1 is : \=
t %8.3lf &quot;, y);<br>=A0 return 0;<br>} <br>/**<br>=A0=A0=A0 Value for s=
in=A0 is : =A0=A0=A0 =A0=A0=A0 0.197 <br>=A0=A0=A0 Value for F1 is : =A0=A0=
=A0 =A0=A0=A0=A0 9.005<br>=A0=A0=A0 */<br></div><div>


thanks a lot<br></div></div></div></div></div></div></div></div></div></div=
></div>
<br>--<br>
<a href=3D"http://mail.python.org/mailman/listinfo/python-list" target=3D"_=
blank">http://mail.python.org/mailman/listinfo/python-list</a><br>
<br></blockquote></div><br></div>

--047d7bdca7c29685b304daa5e65a--