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+// Copyright (C) 2001 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING.  If not, write to the Free
+// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+// 25.3.1 algorithms, sort()
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+
+bool test __attribute__((unused)) = true;
+
+const int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20};
+const int B[] = {10, 20, 1, 11, 2, 12, 3, 13, 4, 14, 5, 15, 6, 16, 7, 17, 8, 18, 9, 19};
+const int C[] = {20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
+const int N = sizeof(A) / sizeof(int);
+const int logN = 3; // ln(N) rounded up
+const int P = 7;
+
+// comparison predicate for stable_sort: order by rightmost digit
+struct CompLast
+{
+  bool
+  operator()(const int x, const int y)
+  { return x % 10 < y % 10; }
+};
+
+// This functor has the equivalent functionality of std::geater<>,
+// but there is no dependency on <functional> and it also tracks the
+// number of invocations since creation.
+class Gt
+{
+public:
+  static int count() { return itsCount; }
+  static void reset() { itsCount = 0; }
+  
+  bool
+  operator()(const int& x, const int& y)
+  {
+    ++itsCount;
+    return x > y; 
+  }
+
+private:
+    static int itsCount;
+};
+
+int Gt::itsCount = 0;
+
+// 25.3.2 nth_element()
+void
+test05()
+{
+    using std::nth_element;
+
+    int s1[N];
+    std::copy(B, B + N, s1);
+    VERIFY(std::equal(s1, s1 + N, B));
+
+    int* pn = s1 + (N / 2) - 1;
+    nth_element(s1, pn, s1 + N);
+    for (const int* i = pn; i < s1 + N; ++i) VERIFY(!(*i < *pn));
+
+    CompLast pred;
+    nth_element(s1, pn, s1 + N, pred);
+    for (const int* i = pn; i < s1 + N; ++i) VERIFY(!pred(*i, *pn));
+}
+
+int
+main()
+{
+  test05();
+  return 0;
+}