Re: copying elements from a <list> to <deque>

From:
Kai-Uwe Bux <jkherciueh@gmx.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 25 Sep 2007 02:24:33 -0700
Message-ID:
<fdak58$vh$1@murdoch.acc.Virginia.EDU>
Erik Wikstr?m wrote:

On 2007-09-25 09:59, arnuld wrote:

It works fine. any advice on making it better or if I can
improve my C++ coding skills:

/* C++ Primer - 4/e
 *
 * Chapter 9 - Sequential Containers
 * exercise 9.18 - STATEMENT
 * Write a program to copy elements from a list of
 "ints" * to 2 "deques". The list elements that are even should go into
 one deque * and even elements should go into 2nd deque.
 *
 */

#include <iostream>
#include <list>
#include <deque>
#include <algorithm>
#include <iterator>

int main()
{
  std::cout << "enter some integers: ";
  std::list<int> ilist;
  /* copy elements from std::cin into ilist */
  std::copy( (std::istream_iterator<int>( std::cin )),
(std::istream_iterator<int>()),
std::back_inserter( ilist ) );

  std::deque<int> deque_of_evens;
  std::deque<int> deque_of_odds;
  /* copy even elements into 1 deque and odds into the other */
  for( std::list<int>::const_iterator iter = ilist.begin();
       iter != ilist.end();
       ++iter)
    {
      if( *iter % 2 == 0 )
{
deque_of_evens.push_back( *iter );
}
      else
{
deque_of_odds.push_back( *iter );
}
    }

      
  std::cout << "\n Printing Deque of Even Integers: ";
  std::copy( deque_of_evens.begin(),
deque_of_evens.end(),
std::ostream_iterator<int>( std::cout, " " ) );

  std::cout << "\n\n Printing Deque of Odd Integers: ";
  std::copy( deque_of_odds.begin(),
deque_of_odds.end(),
std::ostream_iterator<int>( std::cout, " " ) );

  std::cout << std::endl;
 
  return 0;
}


You should research the (IMO badly named) remove_copy_if algorithm and
create a predicate to determine if the element is even or not.


And: you should implement the missing (sic!) copy_if algorithm and use the
same predicate for the other copy job.

Best

Kai-Uwe Bux

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