+
++The filter iterator adaptor ... + + + +
+#include <boost/config.hpp>
+#include <algorithm>
+#include <iostream>
+#include <boost/iterator_adaptors.hpp>
+
+struct is_positive_number {
+ bool operator()(int x) { return 0 < x; }
+};
+
+int main()
+{
+ int numbers[] = { 0, -1, 4, -3, 5, 8, -2 };
+ const int N = sizeof(numbers)/sizeof(int);
+
+ std::copy(boost::make_filter_iterator<is_positive_number>(numbers, numbers + N),
+ boost::make_filter_iterator<is_positive_number>(numbers + N, numbers + N),
+ std::ostream_iterator<int>(std::cout, " "));
+ std::cout << std::endl;
+ return 0;
+}
+
+The output is:
++4 5 8 ++ + +The filter iterator adaptors +models ForwardIterator + + + +
+template <class Predicate,
+ class Iterator,
+ class Value = value default,
+ class Pointer = pointer default,
+ class Reference = reference default,
+ class Category = category default,
+ class Distance = difference type default>
+class filter_iterator_generator
+{
+ typedef ... type;
+ typedef ... policies_type;
+}
+
+
++show another example and explain defaults... + + +
+template <class Predicate, class Iterator> +inline typename detail::filter_generator<Predicate, Iterator>::type +make_filter_iterator(Iterator first, Iterator last, const Predicate& p = Predicate()) ++ + +
Revised 10 Feb 2001
+© Copyright Jeremy Siek 2000. Permission to copy, use, +modify, sell and distribute this document is granted provided this copyright +notice appears in all copies. This document is provided "as is" +without express or implied warranty, and with no claim as to its suitability for +any purpose.
+ + + + diff --git a/filter_iterator_example.cpp b/filter_iterator_example.cpp new file mode 100644 index 0000000..e4bd755 --- /dev/null +++ b/filter_iterator_example.cpp @@ -0,0 +1,30 @@ +// Example of using the filter iterator adaptor from +// boost/iterator_adaptors.hpp. + +// (C) Copyright Jeremy Siek 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