pointing to a member function/method within another function

[uli]

Hi all,
I've learned native C and I'm trying to write now in C++. I want to use a
simple routine from the "Numerical Recipes in C" for using a Newton-Raphson
Method within my c++ class. The Newton-Raphson function for finding roots is
called:
float rtsafe(void (*funcd)(float, float *, float *), float x1, float x2,
float xacc)

'funcd' is the pointer to an external function as common in C. But since I
want to use it with a member function of my class for computing its roots, I
think I can't do that, because member functions are adressed relative to my
class.

Could anyone please give me some hints what I have to do, so that I can use
an external function like this and give it member functions for computation.
(Please apologise my bad style talking about coding...)

Thanx a lot,
uli


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[John Harrison]

Re: pointing to a member function/method within another function


"uli" <NOSPAM_uvb@nur fuerspam.de> wrote in message
news:c7vbkv$pi6 $1@newssrv.muc. infineon.com...[color=blue]
> Hi all,
> I've learned native C and I'm trying to write now in C++. I want to use a
> simple routine from the "Numerical Recipes in C" for using a[/color]
Newton-Raphson[color=blue]
> Method within my c++ class. The Newton-Raphson function for finding roots[/color]
is[color=blue]
> called:
> float rtsafe(void (*funcd)(float, float *, float *), float x1, float[/color]
x2,[color=blue]
> float xacc)
>
> 'funcd' is the pointer to an external function as common in C. But since I
> want to use it with a member function of my class for computing its roots,[/color]
I[color=blue]
> think I can't do that, because member functions are adressed relative to[/color]
my[color=blue]
> class.
>
> Could anyone please give me some hints what I have to do, so that I can[/color]
use[color=blue]
> an external function like this and give it member functions for[/color]
computation.[color=blue]
> (Please apologise my bad style talking about coding...)
>[/color]

Hopefully this gives the idea.

float rtsafe(MyClass* my_class, void (MyClass::*func d)(float, float *,
float *), float x1, float x2, float xacc)
{
(my_class->*funcd)(a, b, c);
}

john

[Karl Heinz Buchegger]

Re: pointing to a member function/method within another function

uli wrote:[color=blue]
>
> Hi all,
> Could anyone please give me some hints what I have to do, so that I can use
> an external function like this and give it member functions for computation.
> (Please apologise my bad style talking about coding...)[/color]

Check the FAQ

http://www.parashift.com/c++-faq-lite/pointers-to-members.html

--
Karl Heinz Buchegger
kbuchegg@gascad .at

[uli]

Re: pointing to a member function/method within another function

Thank you a lot for your quick responses. I think that are the Infos I
need...
uli

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