libstdc++-v3/testsuite/25_algorithms/next_permutation/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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17 // USA.
  18
  19 // 25.3.9 [lib.alg.permutation.generators]
  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::bidirectional_iterator_wrapper;
  27 using std::next_permutation;
  28
  29 typedef test_container<int, bidirectional_iterator_wrapper> Container;
  30
  31 void
  32 test1()
  33 {
  34   // Note: The standard is unclear on what should happen in this case.
  35   // This seems the only really sensible behaviour, and what is done.
  36   int array[] = {0};
  37   Container con(array, array);
  38   VERIFY(!next_permutation(con.begin(), con.end()));
  39 }
  40
  41 void
  42 test2()
  43 {
  44   int array[] = {0};
  45   Container con(array, array + 1);
  46   VERIFY(!next_permutation(con.begin(), con.end()));
  47 }
  48
  49 void
  50 test3()
  51 {
  52   int array[] = {0, 3};
  53   Container con(array, array + 2);
  54   VERIFY(next_permutation(con.begin(), con.end()));
  55   VERIFY(array[0] == 3 && array[1] == 0);
  56   VERIFY(!next_permutation(con.begin(), con.end()));
  57   VERIFY(array[0] == 0 && array[1] == 3);
  58 }
  59
  60 void
  61 test4()
  62 {
  63   int array[6] = {0, 1, 2, 3, 4, 5};
  64   Container con(array, array + 6);
  65   for(int i = 0 ; i < 719; ++i)
  66     {
  67       int temp_array[6];
  68       std::copy(array, array + 6, temp_array);
  69       VERIFY(next_permutation(array, array + 6));
  70       VERIFY(std::lexicographical_compare(temp_array, temp_array + 6,
  71                                           array, array + 6));
  72     }
  73   VERIFY(!next_permutation(array,array + 6));
  74   for(int i = 0; i < 6; ++i)
  75     VERIFY(array[i] == i);
  76 }
  77
  78 int main()
  79 {
  80   test1();
  81   test2();
  82   test3();
  83   test4();
  84 }