new files

[SVN r9144]

projection_iterator_example.cpp

@@ -0,0 +1,96 @@
+// (C) Copyright Jeremy Siek 2000. 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 <boost/config.hpp>
+#include <list>
+#include <iostream>
+#include <iterator>
+#include <algorithm>
+#include <string>
+#include <boost/iterator_adaptors.hpp>
+
+struct personnel_record {
+  personnel_record(std::string n, int id) : m_name(n), m_ID(id) { }
+  std::string m_name;
+  int m_ID;
+};
+
+struct select_name {
+  typedef personnel_record argument_type;
+  typedef std::string result_type;
+  const std::string& operator()(const personnel_record& r) const {
+    return r.m_name;
+  }
+  std::string& operator()(personnel_record& r) const {
+    return r.m_name;
+  }
+};
+
+struct select_ID {
+  typedef personnel_record argument_type;
+  typedef int result_type;
+  const int& operator()(const personnel_record& r) const {
+    return r.m_ID;
+  }
+  int& operator()(personnel_record& r) const {
+    return r.m_ID;
+  }
+};
+
+int main(int, char*[])
+{
+  std::list<personnel_record> personnel_list;
+
+  personnel_list.push_back(personnel_record("Barney", 13423));
+  personnel_list.push_back(personnel_record("Fred", 12343));
+  personnel_list.push_back(personnel_record("Wilma", 62454));
+  personnel_list.push_back(personnel_record("Betty", 20490));
+
+  // Example of using projection_iterator_generator
+  // to print out the names in the personnel list.
+
+  boost::projection_iterator_generator<select_name,
+    std::list<personnel_record>::iterator>::type
+    personnel_first(personnel_list.begin()),
+    personnel_last(personnel_list.end());
+
+  std::copy(personnel_first, personnel_last,
+            std::ostream_iterator<std::string>(std::cout, "\n"));
+  std::cout << std::endl;
+  
+  // Example of using projection_iterator_pair_generator
+  // to assign new ID numbers to the personnel.
+  
+  typedef boost::projection_iterator_pair_generator<select_ID,
+    std::list<personnel_record>::iterator,
+    std::list<personnel_record>::const_iterator> PairGen;
+
+  PairGen::iterator ID_first(personnel_list.begin()),
+    ID_last(personnel_list.end());
+
+  int new_id = 0;
+  while (ID_first != ID_last) {
+    *ID_first = new_id++;
+    ++ID_first;
+  }
+
+  PairGen::const_iterator const_ID_first(personnel_list.begin()),
+    const_ID_last(personnel_list.end());
+
+  std::copy(const_ID_first, const_ID_last,
+            std::ostream_iterator<int>(std::cout, " "));
+  std::cout << std::endl;
+  std::cout << std::endl;
+  
+  // Example of using make_const_projection_iterator()
+  // to print out the names in the personnel list again.
+  
+  std::copy
+    (boost::make_const_projection_iterator<select_name>(personnel_list.begin()),
+     boost::make_const_projection_iterator<select_name>(personnel_list.end()),
+     std::ostream_iterator<std::string>(std::cout, "\n"));
+
+  return 0;
+}