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                       Standard C++ Library
             Copyright 1998, Rogue Wave Software, Inc.


NAME
     back_insert_iterator, back_inserter

      - An insert iterator used to insert items at the end  of  a
     collection.



SYNOPSIS
     #include <iterator>
     template <class Container>
     class back_insert_iterator;



DESCRIPTION
     Insert iterators let you insert new elements into a  collec-
     tion  rather  than copy a new element's value over the value
     of an existing element.  The  class_back_insert_iterator  is
     used  to  insert items at the end of a collection. The func-
     tion   back_inserter    creates    an    instance    of    a
     back_insert_iterator  for  a  particular  collection type. A
     back_insert_iterator can be used with vectors,  deques,  and
     lists, but not with maps or sets.



INTERFACE
     template <class Container>
     class back_insert_iterator
        : public iterator <output_iterator_tag, void, void, void,
         void> {

     protected:
       Container* container;
     public:
       typedef Container container_type;
       explicit back_insert_iterator (Container&);
       back_insert_iterator<Container>&
        operator=
               (const typename Container::const_reference value);
       back_insert_iterator<Container>& operator* ();
       back_insert_iterator<Container>& operator++ ();
       back_insert_iterator<Container> operator++ (int);
     };
     template <class Container>
     back_insert_iterator<Container> back_inserter (Container&);



TYPES
     container_type


        The type of container acted on by this iterator.



CONSTRUCTORS
     explicit
     back_insert_iterator (Container& x);


        Constructor.     Creates     an     instance     of     a
        back_insert_iterator associated with container x.



OPERATORS
     back_insert_iterator<Container>&
     operator= (const typename Container::value_type& value);


        Inserts a copy of value on the end of the container,  and
        returns *this.



     back_insert_iterator<Container>&
     operator* ();


        Returns *this.



     back_insert_iterator<Container>&
     operator++ ();
     back_insert_iterator<Container>
     operator++ (int);


        Increments the input iterator and returns *this.

HELPER FUNCTIONS
     template <class Container>
     back_insert_iterator<Container>
     back_inserter (Container& x)


        Returns a back_insert_iterator that inserts  elements  at
        the  end  of  container  x.  This  function allows you to
        create insert iterators inline.



EXAMPLE
     //
     // ins_itr.cpp
     //
      #include <iterator>
      #include <deque>
      #include <iostream>
     using namespace std;

     int main ()
      {
        //
        // Initialize a deque using an array.
        //
       int arr[4] = { 3,4,7,8 };
       deque<int> d(arr+0, arr+4);
        //
        // Output the original deque.
        //
       cout << "Start with a deque: " << endl << "     ";
       copy(d.begin(), d.end(),
            ostream_iterator<int,char>(cout," "));
        //
        // Insert into the middle.
        //
       insert_iterator<deque<int> > ins(d, d.begin()+2);
        *ins = 5; *ins = 6;
        //
        // Output the new deque.
        //
       cout << endl << endl;
       cout << "Use an insert_iterator: " << endl << "     ";
       copy(d.begin(), d.end(),
            ostream_iterator<int,char>(cout," "));
        //
        // A deque of four 1s.
        //
       deque<int> d2(4, 1);
        //
        // Insert d2 at front of d.
        //
       copy(d2.begin(), d2.end(), front_inserter(d));
        //
        // Output the new deque.
        //
       cout << endl << endl;
       cout << "Use a front_inserter: " << endl << "     ";
       copy(d.begin(), d.end(),
            ostream_iterator<int,char>(cout," "));
        //
        // Insert d2 at back of d.
        //
       copy(d2.begin(), d2.end(), back_inserter(d));
        //
        // Output the new deque.
        //
       cout << endl << endl;
       cout << "Use a back_inserter: " << endl << "     ";
       copy(d.begin(), d.end(),
            ostream_iterator<int,char>(cout," "));
       cout << endl;

       return 0;
      }

     Program Output



     Start with a deque:
         3 4 7 8
     Use an insert_iterator:
         3 4 5 6 7 8
     Use a front_inserter:
         1 1 1 1 3 4 5 6 7 8
     Use a back_inserter:
         1 1 1 1 3 4 5 6 7 8 1 1 1 1



WARNINGS
     If your compiler does not support default  template  parame-
     ters,  then you always need to supply the Allocator template
     argument. For instance, you have to write:

     vector<int,allocator<int> >

     instead of:
     vector<int>

     If your compiler does not support namespaces,  then  you  do
     not need the using declaration for std.



SEE ALSO
     Insert_Iterators

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