How to get the cubic root for complex number?

[Peng Yu]

Hi,

I'm wondering how to get the cubic root for a complex number? It seems
that cbrt does not work complex numbers.

Thanks,
Peng

#include <complex>
#include <iostream>

int main () {
std::complex<doublex(2, 2);
std::cout << cbrt(x) << std::endl;
}

[Kai-Uwe Bux]

Peng Yu wrote:

Hi,

I'm wondering how to get the cubic root for a complex number? It seems
that cbrt does not work complex numbers.

I cannot find cbrt() in the standard anyway.

Thanks,
Peng

#include <complex>
#include <iostream>

int main () {
std::complex<doublex(2, 2);
std::cout << cbrt(x) << std::endl;
}

#include <cmath>
#include <complex>
#include <iostream>
#include <ostream>

int main () {
std::complex<doublex(2, 2);
std::complex<doubler = std::pow( x, 1.0/3.0 );
std::cout << r << '\n'
<< r*r*r << '\n';
}
Best

Kai-Uwe Bux

[Peng Yu]

On Sep 9, 8:10 pm, Kai-Uwe Bux <[e-mail]:

Peng Yu wrote:

Hi,

I'm wondering how to get the cubic root for a complex number? It seems
that cbrt does not work complex numbers.

I cannot find cbrt() in the standard anyway.

cbrt() is conforming to C99.

Thanks,
Peng

[Jack Klein]

On Tue, 9 Sep 2008 18:20:45 -0700 (PDT), Peng Yu <Pe*******@gmail.com>
wrote in comp.lang.c++:

On Sep 9, 8:10 pm, Kai-Uwe Bux <[e-mail]:

Peng Yu wrote:

Hi,

I'm wondering how to get the cubic root for a complex number? It seems
that cbrt does not work complex numbers.

I cannot find cbrt() in the standard anyway.

cbrt() is conforming to C99.

....then wait until it is added to C++, which it probably will be.
Because it is not part of the standard C++ library today.

--
Jack Klein
Home: http://JK-Technology.Com
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[dot]

Jack Klein wrote:

On Tue, 9 Sep 2008 18:20:45 -0700 (PDT), Peng Yu <Pe*******@gmail.com>
wrote in comp.lang.c++:

>On Sep 9, 8:10 pm, Kai-Uwe Bux <[e-mail]:

>>Peng Yu wrote:
Hi,
I'm wondering how to get the cubic root for a complex number? It seems
that cbrt does not work complex numbers.
I cannot find cbrt() in the standard anyway.

cbrt() is conforming to C99.

...then wait until it is added to C++, which it probably will be.
Because it is not part of the standard C++ library today.

You don't need to wait. Write yourself a function to call cbrt(),
compile under C99, link it with the rest of your program.

Ben