STL templates (and vectors)

[D_C]

I'm doing some pre-code planning, I am curious if/how possible the following templates would be? For my example, Class A contains a vector of Class B, which contains a vector of Class C, which contains a vector of Class D. It's quite modular.


Template 1 - trim()
I would like to write a template that can take in a vector, and automatically trim it's capacity down to it's size. I have to do this in two places, with different types of vectors, vector<C> and vector<D>. The code for trim() is really simple:

vector<object_type>(v).swap(v);

Also, this is a simplified version of Template 2, which I am more interested in using.


Template 2 - cascade()
My plan has a lot of symmetry, it's like class A is the top tier, and then I want the calls to propagate down into the lower tiers. For example in the constructor A() I call constructor B() which calls constructor C() which calls constructor D(). As a result, I have many functions which are pseudocoded:

// properly declare it as the iterator for vector PARAM1
for(it = PARAM1.begin; it != PARAM1.end; it++)
    it->PARAM2();

I am assuming if we pass a pointer to the vector, it will remember the object type, and size, unlike an array. Is there anything else I should know?

[Banfa]

I'm doing some pre-code planning, I am curious if/how possible the following templates would be? For my example, Class A contains a vector of Class B, which contains a vector of Class C, which contains a vector of Class D. It's quite modular.

Not a problem (as long as you stay inside the memory constraints of your system.

Template 1 - trim()
I would like to write a template that can take in a vector, and automatically trim it's capacity down to it's size. I have to do this in two places, with different types of vectors, vector<C> and vector<D>. The code for trim() is really simple:

vector<object_type>(v).swap(v);

Also, this is a simplified version of Template 2, which I am more interested in using.

I would be inclined just to create a new emplate class that inherits from vector

template <class T> class MyVector : public vector<T>
{
public:
    MyVector() : vector() {};
    trim(){vector<object_type>(v).swap(v);};
}

Template 2 - cascade()
I am assuming if we pass a pointer to the vector, it will remember the object type, and size, unlike an array. Is there anything else I should know?

Yes but the type for a vector of pointers is pointer to A and the size (on mist 32 bit systems today) is 4 bytes. You may want a vector of objects in which case you wont be passing pointers.

It's the difference between the 2 declarations

vector<double> vd;
vector<double *> vpd;