insert_iterator : custom iterater « STL Algorithms Iterator « C++ Tutorial

1. C++ Tutorial
2. STL Algorithms Iterator
3. custom iterater

/* 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 <set>
#include <list>
#include <algorithm>

using namespace std;

/* PRINT_ELEMENTS()
 * - prints optional C-string optcstr followed by
 * - all elements of the collection coll
 * - separated by spaces
 */
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
    typename T::const_iterator pos;

    std::cout << optcstr;
    for (pos=coll.begin(); pos!=coll.end(); ++pos) {
        std::cout << *pos << ' ';
    }
    std::cout << std::endl;
}

int main()
{
    set<int> coll;

    // create insert iterator for coll
    // - inconvenient way
    insert_iterator<set<int> > iter(coll,coll.begin());

    // insert elements with the usual iterator interface
    *iter = 1;
    iter++;
    *iter = 2;
    iter++;
    *iter = 3;

    PRINT_ELEMENTS(coll,"set:  ");

    // create inserter and insert elements
    // - convenient way
    inserter(coll,coll.end()) = 44;
    inserter(coll,coll.end()) = 55;

    PRINT_ELEMENTS(coll,"set:  ");

    // use inserter to insert all elements into a list
    list<int> coll2;
    copy (coll.begin(), coll.end(),           // source
          inserter(coll2,coll2.begin()));     // destination

    PRINT_ELEMENTS(coll2,"list: ");

    // use inserter to reinsert all elements into the list before the second el
ement
    copy (coll.begin(), coll.end(),           // source
          inserter(coll2,++coll2.begin()));   // destination

    PRINT_ELEMENTS(coll2,"list: ");
}

set:  1 2 3
set:  1 2 3 44 55
list: 1 2 3 44 55
list: 1 1 2 3 44 55 2 3 44 55