Re: sorting the input

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 10 Sep 2008 09:29:16 -0700 (PDT)
Message-ID:
<ed84aa41-5520-4bb2-b3bd-f66b05369b34@26g2000hsk.googlegroups.com>
On Sep 10, 3:13 pm, ??? <lostgold...@163.com> wrote:

arnuld ??:

A program that asks user to input words and then prints them
in alphabetical order. I have used vectors to accomplish
task. That left me wondering with 2 questions:

  1) whether list will be a good idea. I am basically
  concerned about CPU efficiency.


It might be better to worry about whether the code works or not.

  2) Is the program is a C++ program or C program written in
  C++.


you wrote nice code of STL style, but i think use typedef to
redefine some iterator type is better to read.


Question of taste. I find that a lot of such typedef's actually
make the code harder to read. I know exactly what an
std::vector<>::iterator is and does; I don't know what a
VectIter is or does.

in my point of view,the std::sort works better with
std::vector than std::list,


That's putting it mildly. Calling std::sort with iterators from
an std::list is undefined behavior, and I suspect that it will
fail to compile with most compilers. std::list does have a sort
member function, however.

but, the std::vector<typename T>::push_back is less efficient
than std::list<>::insert.


Are you sure about that? I'm not. In the few times I've
actually measured, std::vector<>push_back has turned out to be
faster than std::list<>::push_back.

About the only time you would want to use std::list<> is when
you need to insert and/or erase somewhere in the middle of the
sequence. And even then, only if the sequence is long, and the
objects expensive to copy.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
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