libstdc++-v3/testsuite/25_algorithms/nth_element/constexpr.cc

   1 // Copyright (C) 2019-2024 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do compile { target c++20 } }
  19
  20 #include <algorithm>
  21 #include <array>
  22 #include <functional>
  23
  24 constexpr bool
  25 test()
  26 {
  27   auto ok = true;
  28
  29   std::array<int, 12> ar0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
  30
  31   std::nth_element(ar0.begin(), ar0.begin() + 5, ar0.end());
  32   ok = ok && ar0[5] == 5;
  33
  34   std::sort(ar0.begin(), ar0.end(), std::greater<>());
  35   std::nth_element(ar0.begin(), ar0.begin() + 5, ar0.end(), std::greater<>());
  36   ok = ok && ar0[5] == 6;
  37
  38   return ok;
  39 }
  40
  41 static_assert(test());