Search
Best way to "convert" a real to ireal
Sep 13, 2007
Carsten Sørensen
Sep 13, 2007
Christian Kamm
Sep 13, 2007
Carsten Sørensen
Sep 14, 2007
Christian Kamm
```Hi,

With D's support for complex math I thought it would be fun to do a Mandelbrot explorer.

It's all working fine but in the process of writing it, a few questions popped into my head.

creal have .re and .im properties, but .im returns a real, not an ireal as I would expect. Is there another property that will return the imaginary part as an ireal? I can't seem to find the creal properties documented anywhere.

Since .im returns a real I sometimes have to convert it back to an ireal.

This doesn't work, im is now zero.
---
creal c = 1.0 + 1.0i;
ireal im = cast(ireal)c.im;
---

---
creal c = 1.0 + 1.0i;
ireal im = c.im * 1.0i;
---

but this seems a bit clumsy... is there a better way? Or better yet, a creal property that will actually retrieve the imaginary part as an ireal?

Thanks,
Carsten Sørensen
```
```> creal have .re and .im properties, but .im returns a real, not an ireal as I would expect. Is there another property that will return the imaginary part as an ireal? I can't seem to find the creal properties documented anywhere.

I don't think there is. The properties are mentioned here
http://www.digitalmars.com/d/property.html
among the properties of floating point types, but not really documented.

I expect .im behaves the way it does since that's how it's used in mathematics. So c.im * 1.0i is the right way to make it an ireal.

Christian
```
```Christian Kamm wrote:
> I don't think there is. The properties are mentioned here
> http://www.digitalmars.com/d/property.html
> among the properties of floating point types, but not really documented.
>
> I expect .im behaves the way it does since that's how it's used in
> mathematics. So c.im * 1.0i is the right way to make it an ireal.

Thanks for your reply! I suppose (well, hope really) the compiler does the right thing when multiplying by 1.0i.

I just had a brainwave regarding the imaginary part of creal -

---
creal c = 1.0 + 1.0i;
ireal i = cast(ireal)c;
---

does exactly what I want. Isn't it just obvious in hindsight...

Best regards,
Carsten Sørensen
```
```> I just had a brainwave regarding the imaginary part of creal -
>
> ---
> creal c = 1.0 + 1.0i;
> ireal i = cast(ireal)c;
> ---
>
> does exactly what I want. Isn't it just obvious in hindsight...

For your peace of mind: with optimizations enabled, the cast(ireal) and the .im * i seem to produce exactly the same code.

Cheers,
Christian
```