🚀 go-pugleaf

In attempting to implement the vector<T, Allocator> class, I have two 
questions about the insert() functions.  I am working from the April 1995 
working draft, so I apologize if any of my questions have already been 
resolved.

Under subclause 23.2.5.6 vector modifiers, we have rules for the insert() 
functions.  I read the following:

"Notes:  Causes reallocation if the new size is greater than the old 
capacity.  If no reallocation happens, all the iterators and references 
before the insertion point remain valid."

What is not clear to me, and this is probably perfectly obvious, but what 
insertion points are allowed?  This is my first question.  As a minimum, 
I guess that begin() <= position <= end().  Are insertion points allowed 
outside of these values?  I ask this because we are allowed to reserve 
and reallocate memory.  For example, here is a case where the new size 
does not exceed the capacity, and the capacity exceeds the old size.  Let 
us also say that we have some print function that writes values from 
begin() to end() to standard output, and that ## denotes denotes the 
result of printing uninitialized memory.

vector<int allocator> V(3);
cout << V.size() << endl;          // prints 3
cout << V.capacity() << endl;    // prints 3
V.print();                                    // prints 0 0 0

V.reserve(5);
cout << V.size() << endl;          // prints 3
cout << V.capacity() << endl;    // prints 5
V.print();                                    // prints 0 0 0

Can we insert a value at the new fifth position?

V.insert(V.end() + 2, 12);          // insert 12 at 5th position
V.print();                                 // prints 0 0 0 ## 12

Or a value before the first position?

V.insert(V.begin() - 1, 12);          // insert 12 before 1st position
V.print();                                 // 12 ##  0 0 0

If these cases are permissable, would it also be allowable to use these 
insertion points without previously reserving the required space forcing 
a reallocation?

As my second question, I see that we have:

iterator insert(iterator position, const T& x = T());
void insert(iterator position, size_type n, const T& x);
template <class T>
void insert(iterator position, InputerIterator first, InputIterator last);


Shouldn't we also be able to insert vectors, like

void insert(iterator position, const vector<T,
     Allocator>& v);

.. or better still ...

template <Allocator2>
void insert(iterator position,
     const vector<T, Allocator2>& v);  ?

I apologize once again, if I am asking questions gone over before.

          Karen
	

	
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