R16 iterators [SOLVED]

On 21/10/2014 at 08:49, xxxxxxxx wrote:

User Information:
Cinema 4D Version:   R16 
Platform:   Windows  ;   
Language(s) :     C++  ;

---------
Hi,

I'm having trouble with R16 iterators.
I must first confess that I don't use iterators in C++ because I think it's very ugly looking code. But I would like to force myself to use them more often.

This code yells at me that <BaseArray<Int> is not a template.
I do have #include "c4d_misc.h" in my code. Do I need to write my own template?
How do I make this work?

    maxon::BaseArray<Int> myarr;  
  
  for (maxon::AutoIterator<BaseArray<Int> > it(myarr); it; ++it)  
  {  
      //... do something with *it or it->  
  }

Can someone also please post an example how to use an R16 iterator to iterate the objects in the hierarchy?

Thanks,
-ScottA

On 21/10/2014 at 08:54, xxxxxxxx wrote:

It's similar to the STD iterators.

for (maxon::BaseArray<Int>::Iterator it = myarr.Begin(); it != myarr.End(); ++it)
{
    // ...
}

I prefer to use auto for iterators.

for (auto it = myarr.Begin(); it != myarr.End(); ++it)
{
    // ...
}

There's also a FOREACH macro in the SDK. I think you use it like this

FOREACH (it, myarr)
{
    // ...
}

On 21/10/2014 at 09:59, xxxxxxxx wrote:

Thanks Niklas.
This is what I have working so far:

    //Create an array and fill it with some data  
  maxon::BaseArray<Int> myarr;      
  for(Int32 i = 0; i < 10; i++){ myarr.Append(i); }  
  
  //Iterate through the array using an iterator  
  //The iterator 'it' is the value of each array element  
  //for(maxon::BaseArray<Int>::Iterator it = myarr.Begin(); it != myarr.End(); ++it)  
  for(auto it = myarr.Begin(); it != myarr.End(); ++it)  
  {  
      auto value = *it;      
      GePrint(String::IntToString(value));  
  
      if (*it == 5) { GePrint("found value of 5"); break; }          
  }  
  
  FOREACH(it, myarr)  
  {  
      GePrint("ForEach macro results: " + String::IntToString(*it));  
  }

Now I just need to figure out how to iterate objects.

-ScottA

P.S. @ MAXON: Please document these things better with examples like the one I just posted

On 21/10/2014 at 10:09, xxxxxxxx wrote:

What do you mean with "how to iterate objects"?

On 21/10/2014 at 10:38, xxxxxxxx wrote:

Something like this:

  
      FOREACH(obj, MyAtomArray)  
      {  
          GePrint(obj->GetName());  
      }  

I know how to do this with an AtomArray and a standard for() loop.
But I'd like to use the new FOREACH and/or iterators instead.

-ScottA

On 21/10/2014 at 12:04, xxxxxxxx wrote:

The AtomArray has no built-in iterator capabilities. You have to use GetIndex().

On 21/10/2014 at 12:11, xxxxxxxx wrote:

Well. That's just an example.
Is there no way to use the new iterators for iterating object hierarchies?

-ScottA

On 21/10/2014 at 12:13, xxxxxxxx wrote:

Sorry, forget this post. I wasn't aware you were already a few steps further...

Hi Scott,

I'm not quite sure, as you seemed to already have it. Here's your example with PolygonObject:

maxon::BaseArray<PolygonObject*> polyarr;
for (Int32 i = 0; i < 10; i++) { polyarr.Append(PolygonObject::Alloc(8, 6)); }
  
//Iterate through the array using an iterator
//The iterator 'it' is the value of each array element
for (auto it = polyarr.Begin(); it != polyarr.End(); ++it) {
  auto pPObj = *it;
  GePrint(String::IntToString(pPObj->GetPolygonCount()));
  
  if (pPObj->GetPolygonCount() == 6) { GePrint("polyarr found possible cube"); break; }
}
  
FOREACH(it, polyarr)
{
  GePrint("polyarr ForEach macro results: " + String::IntToString((*it)->GetPolygonCount()));
}

On 21/10/2014 at 12:36, xxxxxxxx wrote:

Anyway, I'll add iterators on our ever growing todo list of documentation topics.

Regarding your question: I don't think so (Niklas may correct me, if I'm mistaken). In order to use the iterator, the class to iterate needs to have one defined. Like BaseArray

On 24/10/2014 at 04:57, xxxxxxxx wrote:

That's correct. Only the new array classes support iterators, the old ones don't. That's one of the many advantages the new classes have, and one more reason to use them whenever possible.