libstdc++-v3/testsuite/25_algorithms/partial_sort/2.cc

   1 // Copyright (C) 2001-2016 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 // 25.3.1 algorithms, sort()
  19
  20 #include <algorithm>
  21 #include <testsuite_hooks.h>
  22
  23 bool test __attribute__((unused)) = true;
  24
  25 const int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20};
  26 const int B[] = {10, 20, 1, 11, 2, 12, 3, 13, 4, 14, 5, 15, 6, 16, 7, 17, 8, 18, 9, 19};
  27 const int C[] = {20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
  28 const int N = sizeof(A) / sizeof(int);
  29 const int logN = 3; // ln(N) rounded up
  30 const int P = 7;
  31
  32 // comparison predicate for stable_sort: order by rightmost digit
  33 struct CompLast
  34 {
  35   bool
  36   operator()(const int x, const int y)
  37   { return x % 10 < y % 10; }
  38 };
  39
  40 // This functor has the equivalent functionality of std::geater<>,
  41 // but there is no dependency on <functional> and it also tracks the
  42 // number of invocations since creation.
  43 class Gt
  44 {
  45 public:
  46   static int count() { return itsCount; }
  47   static void reset() { itsCount = 0; }
  48
  49   bool
  50   operator()(const int& x, const int& y)
  51   {
  52     ++itsCount;
  53     return x > y;
  54   }
  55
  56 private:
  57     static int itsCount;
  58 };
  59
  60 int Gt::itsCount = 0;
  61
  62 // 25.3.1.3 partial_sort()
  63 void
  64 test03()
  65 {
  66     int s1[N];
  67     std::copy(B, B + N, s1);
  68     VERIFY(std::equal(s1, s1 + N, B));
  69
  70     std::partial_sort(s1, s1 + P, s1 + N);
  71     VERIFY(std::equal(s1, s1 + P, A));
  72
  73     Gt gt;
  74     gt.reset();
  75     std::partial_sort(s1, s1 + P, s1 + N, gt);
  76     VERIFY(std::equal(s1, s1 + P, C));
  77 }
  78
  79 int
  80 main()
  81 {
  82   test03();
  83   return 0;
  84 }