Re: disadvantages of using STL
On Mar 17, 10:05 pm, "Alf P. Steinbach" <al...@start.no> wrote:
* Victor Bazarov:
Pallav singh wrote:
On Mar 18, 1:36 am, Victor Bazarov <v.Abaza...@comAcast.net> wrote:
Pallav singh wrote:
Q What are the disadvantages of using STL ?
The main disadvantage is that you need to learn those at
least somewhat before you can use them. All the other
disadvantages pale in comparison.
MFC CMap (works much faster than STL map because STL
implementation is tree-based while MFC one is hash-based).
Uh... MFC CMap, what?
It seems Pallav Singth thinks a that a similarity of names
means roughly equivalent functionality.
If it's true that MFC CMap is hash-based, then that is a hash
table, presumably without simple O(n) traversal of elements,
and certainly not in sorted order, but on the other hand
offering O(1) insertion and look-up -- a different trade-off
from the one in std::map, and used for different purposes.
Note that hash tables are only O(1) if you have a perfect
hashing function. They can be close with a very good hashing
function, but approch O(n) with a very bad one. Writing a good
hashing function isn't trivial.
The result is that std::map is sufficiently fast most of the
time, and much easier to use, unless you've actually done some
research on hashing, and have all of the necessary tools in your
tool kit.
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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