libstdc++-v3/testsuite/25_algorithms/nth_element/1.cc

   1 // Copyright (C) 2005-2025 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 // 25.3.2 [lib.alg.nth.element]
  19
  20 #include <algorithm>
  21 #include <testsuite_hooks.h>
  22 #include <testsuite_iterators.h>
  23
  24 using __gnu_test::test_container;
  25 using __gnu_test::random_access_iterator_wrapper;
  26 using std::nth_element;
  27 using std::partial_sort;
  28
  29 typedef test_container<int, random_access_iterator_wrapper> Container;
  30
  31 void
  32 test1()
  33 {
  34   int array[]={0};
  35   Container con(array, array);
  36   partial_sort(con.begin(), con.begin(), con.end());
  37 }
  38
  39 void
  40 test2()
  41 {
  42   int array[]={2,1,0};
  43   Container con(array, array + 2);
  44   partial_sort(con.begin(), con.begin(), con.end());
  45   partial_sort(con.begin(), con.end(), con.end());
  46 }
  47
  48 void
  49 test3()
  50 {
  51   int array[] = {6, 5, 4, 3, 2, 1, 0};
  52   Container con(array, array + 7);
  53   nth_element(con.begin(), con.it(3), con.end());
  54   for(int i = 0; i < 3; ++i)
  55     VERIFY(array[i] < array[3]);
  56   for(int i = 4; i < 7; ++i)
  57     VERIFY(array[3] < array[i]);
  58 }
  59
  60 void
  61 test4()
  62 {
  63   int array[] = {0, 6, 1, 5, 2, 4, 3};
  64   Container con(array,array + 7);
  65   nth_element(con.begin(), con.it(3), con.end());
  66   for(int i = 0; i < 3; ++i)
  67     VERIFY(array[i] < array[3]);
  68   for(int i = 4; i < 7; ++i)
  69     VERIFY(array[3] < array[i]);
  70 }
  71
  72 int
  73 main()
  74 {
  75   test1();
  76   test2();
  77   test3();
  78   test4();
  79 }