Re: [C++] Vectors & Dynamic allocation

From: Francis Glassborow (francis_at_robinton.demon.co.uk)
Date: 04/30/04 

Date: Fri, 30 Apr 2004 10:35:48 +0100

In message <bm44909io91ceu7kt4kjhforg3nmvjp8m8@4ax.com>, Robert W Hand
<rwhand@NOSPAMoperamail.com> writes
>In the section of the Standard devoted to std::vector<T>::erase, there
>is a paragraph labeled "Complexity". It states that the destructor of
>T is called the number of times equal to the number of elements
>erased,

Indeed it says that, but I do not know why because erase() for vectors
does not remove elements, you have to use std::remove() to do that. All
erase does is to write new values into the erased elements (using copy
assignment).

> but the assignment operator for T is called the number of
>times equal to the number of elements after the erased elements.
>There is no provision for deallocation. Furthermore, since iterators
>before the erasure remain valid, an allocation/deallocation step seems
>impossible. Deallocation/allocation would invalidate all the
>iterators.

And I do not know why it mentions invalidation of iterators as it seems
to me that the iterators remain valid but the values of the objects they
identify changes. 

-- 
Francis Glassborow      ACCU
Author of 'You Can Do It!' see http://www.spellen.org/youcandoit
For project ideas and contributions: http://www.spellen.org/youcandoit/projects

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