Declare an array at .h and create at .cpp

[tonnot]

I'm a little losted...

I want to declare an array of objects at .h file (to say my class that are private). And later, I want to create it :

at .h
a_object *obs[];

at .cpp ???

void the_method_where_I_want_to_create_it.
{
>>>>>> obs=new a_object[20] ?????
But if a_object has an argument at constructor ????
}

If I declare at h.file :
a_object *obs[const 20];
later at .cpp I can do:
obs[0] = new a_object(argument);

I want to create 20 obs into cpp. How ?
I don't know how to do it.
Thanks

[Athar]

Header file:
extern std::vector<a_object> objects;

Implementation file:

void the_method_where_I_want_to_create_it()
{
  for (int i=0;i<20;i++)
  {
    objects.push_back(a_objects(parameters,here));
  }
}

Note that vectors store copies of the objects you pass to push_back.
When the objects is not copyable (or if it is not desirable), you can use ptr_vector:

extern boost::ptr_vector<a_object> objects;
//doesn't need to be the boost one, there are many implementations of ptr_vector 

And the other line changes to:
objects.push_back(new a_object(parameters,here));

It would probably be better to create a class that manages the set of objects instead of simply having a global, generic container. Depends on your situation, though.

[tonnot]

Thanks
And, summarizing, is not posible to declare an array of objects (with or not with parameters at constructor) at h. file and give the dimension later ?

[quirkyusername]

if you stored a pointer and allocated the array dynamically then it is

[tonnot]

Some example ?
I have difficulties to do so when the class contructor are waiting for parameters...
So my_array = new class[5] ????? does not work..

[jsmith]

Yes, you cannot dynamically allocate an array of objects and call any constructor other than the default one.

std::vector<> overcomes this limitation.