Просмотр исходного текста страницы C++/List/list remove

==Good way and bad way to remove elements in a list==


   
<source lang="cpp"> 
 
/* The following code example is taken from the book
 * "The C++ Standard Library - A Tutorial and Reference"
 * by Nicolai M. Josuttis, Addison-Wesley, 1999
 *
 * (C) Copyright Nicolai M. Josuttis 1999.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include <iostream>
#include <list>
#include <algorithm>
using namespace std;
int main()
{
    list<int> coll;
    // insert elements from 6 to 1 and 1 to 6
    for (int i=1; i<=6; ++i) {
        coll.push_front(i);
        coll.push_back(i);
    }
    // remove all elements with value 3
    // - poor performance
    coll.erase (remove(coll.begin(),coll.end(),
                       3),
                coll.end());
    // remove all elements with value 4
    // - good performance
    coll.remove (4);
}
        
  </source>


==Remove all elements with the same value==


   
<source lang="cpp"> 
 
#include <iostream>
using std::cout;
using std::endl;
#include <list>      // list class-template definition
#include <algorithm> // copy algorithm
#include <iterator>  // ostream_iterator
int main()
{
   int array[ 4 ] = { 2, 6, 4, 8 };
   std::list< int > values;      // create list of ints
   std::list< int > otherValues; // create list of ints
   std::ostream_iterator< int > output( cout, " " );
   // insert items in values
   values.push_front( 1 );
   values.push_front( 3 );
   values.push_back( 4 );
   values.push_back( 1 );
   values.push_back( 2 );
   values.push_back( 3 );
   cout << "values contains: ";
   std::copy( values.begin(), values.end(), output );
   values.remove( 1 ); // remove all 1s
   cout << "\n\nvalues contains: ";
   std::copy( values.begin(), values.end(), output );
   cout << endl;
   return 0;
}
 /* 
values contains: 3 1 4 1 2 3
values contains: 3 4 2 3
 */       
  </source>