new files

[SVN r9109]

transform_iterator_example.cpp

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+// (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 <functional>
+#include <algorithm>
+#include <iostream>
+#include <boost/iterator_adaptors.hpp>
+
+int
+main(int, char*[])
+{
+  // This is a simple example of using the transform_iterators class to
+  // generate iterators that multiply the value returned by dereferencing
+  // the iterator. In this case we are multiplying by 2.
+  // Would be cooler to use lambda library in this example.
+
+  int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
+  const int N = sizeof(x)/sizeof(int);
+
+  typedef std::binder1st< std::multiplies<int> > Function;
+  typedef boost::transform_iterator_generator<Function, int*>::type doubling_iterator;
+
+  doubling_iterator i(x, std::bind1st(std::multiplies<int>(), 2)),
+    i_end(x + N, std::bind1st(std::multiplies<int>(), 2));
+
+  std::cout << "multiplying the array by 2:" << std::endl;
+  while (i != i_end)
+    std::cout << *i++ << " ";
+  std::cout << std::endl;
+
+  std::cout << "adding 4 to each element in the array:" << std::endl;
+
+  std::copy(boost::make_transform_iterator(x, std::bind1st(std::plus<int>(), 4)),
+	    boost::make_transform_iterator(x + N, std::bind1st(std::plus<int>(), 4)),
+	    std::ostream_iterator<int>(std::cout, " "));
+  std::cout << std::endl;
+  
+  return 0;
+}
+
+