Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  remove  - Move desired elements to the front of a container, and return an
  iterator that describes where the sequence of desired elements ends.

SYNOPSIS

  #include <algorithm>

  template <class ForwardIterator, class T>
  ForwardIterator
  remove (ForwardIterator first,
         ForwardIterator last,
         const T& value);

DESCRIPTION

  The remove algorithm eliminates all the elements referred to by iterator i
  in the range [first, last)  for  which the following condition holds:  *i
  == value. remove returns an iterator that designates the end of the
  resulting range.  remove is stable, that is, the relative order of the
  elements that are not removed is the same as their relative order in the
  original range.

  remove does not actually reduce the size of the sequence.  It actually
  operates by:  1) copying the values that are to be retained to the front of
  the sequence, and  2) returning an iterator that describes where the
  sequence of retained values ends.  Elements that are after this iterator
  are simply the original sequence values, left unchanged.  Here's a simple
  example:

  Say we want to remove all values of "2" from the following sequence:

       354621271

  Applying the remove algorithm results in the following sequence:

       3546171|XX

  The vertical bar represents the position of the iterator returned by
  remove.  Note that the elements to the left of the vertical bar are the
  original sequence with the "2's" removed.

  If you want to actually delete items from the container, use the following
  technique:

  container.erase(remove(first,last,value),container.end());

COMPLEXITY

  Exactly last1 - first1 applications of the corresponding predicate are
  done.

EXAMPLE

  //
  // remove.cpp
  //
   #include <algorithm>
   #include <vector>
   #include <iterator>
   #include <iostream.h>
  template<class Arg>
  struct all_true : public unary_function<Arg, bool>
   {
    bool operator()(const Arg& x){ return 1; }
   };
  int main ()
   {
    int arr[10] = {1,2,3,4,5,6,7,8,9,10};
    vector<int> v(arr, arr+10);
    copy(v.begin(),v.end(),ostream_iterator<int,char>(cout," "));
    cout << endl << endl;
     // remove the 7
    vector<int>::iterator result =
             remove(v.begin(), v.end(), 7);
     // delete dangling elements from the vector
    v.erase(result, v.end());
    copy(v.begin(),v.end(),ostream_iterator<int,char>(cout," "));
    cout << endl << endl;
     // remove everything beyond the fourth element
    result = remove_if(v.begin()+4,
                       v.begin()+8, all_true<int>());
     // delete dangling elements
    v.erase(result, v.end());
    copy(v.begin(),v.end(),ostream_iterator<int,char>(cout," "));
    cout << endl << endl;
    return 0;
   }
  Output :
  1 2 3 4 5 6 7 8 9 10
  1 2 3 4 5 6 8 9 10
  1 2 3 4
  1 2 4

WARNING

  If your compiler does not support default template parameters, you need to
  always supply the Allocator template argument.  For instance, you will need
  to write :

  vector<int, allocator<int> >

  instead of :

  vector<int>

SEE ALSO

  remove_if, remove_copy, remove_copy_if

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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