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

   1 // Copyright (C) 2005 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 2, 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 COPYING.  If not, write to the Free
  16 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  17 // USA.
  18
  19 // 25.3.2 [lib.alg.nth.element]
  20
  21 #include <algorithm>
  22 #include <testsuite_hooks.h>
  23 #include <testsuite_iterators.h>
  24
  25 using __gnu_test::test_container;
  26 using __gnu_test::random_access_iterator_wrapper;
  27 using std::nth_element;
  28 using std::partial_sort;
  29
  30 typedef test_container<int, random_access_iterator_wrapper> Container;
  31
  32 void
  33 test1()
  34 {
  35   int array[]={0};
  36   Container con(array, array);
  37   partial_sort(con.begin(), con.begin(), con.end());
  38 }
  39
  40 void
  41 test2()
  42 {
  43   int array[]={2,1,0};
  44   Container con(array, array + 2);
  45   partial_sort(con.begin(), con.begin(), con.end());
  46   partial_sort(con.begin(), con.end(), con.end());
  47 }
  48
  49 void
  50 test3()
  51 {
  52   int array[] = {6, 5, 4, 3, 2, 1, 0};
  53   Container con(array, array + 7);
  54   nth_element(con.begin(), con.it(3), con.end());
  55   for(int i = 0; i < 3; ++i)
  56     VERIFY(array[i] < array[3]);
  57   for(int i = 4; i < 7; ++i)
  58     VERIFY(array[3] < array[i]);
  59 }
  60
  61 void
  62 test4()
  63 {
  64   int array[] = {0, 6, 1, 5, 2, 4, 3};
  65   Container con(array,array + 7);
  66   nth_element(con.begin(), con.it(3), con.end());
  67   for(int i = 0; i < 3; ++i)
  68     VERIFY(array[i] < array[3]);
  69   for(int i = 4; i < 7; ++i)
  70     VERIFY(array[3] < array[i]);
  71 }
  72
  73 int
  74 main()
  75 {
  76   test1();
  77   test2();
  78   test3();
  79   test4();
  80 }