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

   1 // Copyright (C) 2014-2019 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-options "-std=gnu++17" }
  19 // { dg-do run { target c++17 } }
  20 // { dg-require-cstdint "" }
  21
  22 #include <algorithm>
  23 #include <random>
  24 #include <testsuite_hooks.h>
  25 #include <testsuite_iterators.h>
  26
  27 std::mt19937 rng;
  28
  29 using std::sample;
  30 using __gnu_test::test_container;
  31 using __gnu_test::input_iterator_wrapper;
  32 using __gnu_test::output_iterator_wrapper;
  33 using __gnu_test::forward_iterator_wrapper;
  34 using __gnu_test::random_access_iterator_wrapper;
  35
  36 void
  37 test01()
  38 {
  39   const int in[] = { 1, 2 };
  40   test_container<const int, random_access_iterator_wrapper> pop(in);
  41   const int sample_size = 10;
  42   int samp[sample_size] = { };
  43
  44   // population smaller than desired sample size
  45   auto it = sample(pop.begin(), pop.end(), samp, sample_size, rng);
  46   VERIFY( it == samp + std::distance(pop.begin(), pop.end()) );
  47   const auto sum = std::accumulate(pop.begin(), pop.end(), 0);
  48   VERIFY( std::accumulate(samp, samp + sample_size, 0) == sum );
  49 }
  50
  51 void
  52 test02()
  53 {
  54   const int in[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
  55   test_container<const int, random_access_iterator_wrapper> pop(in);
  56   const int sample_size = 10;
  57   int samp[sample_size] = { };
  58
  59   auto it = sample(pop.begin(), pop.end(), samp, sample_size, rng);
  60   VERIFY( it == samp + sample_size );
  61
  62   // verify no duplicates
  63   std::sort(samp, it);
  64   auto it2 = std::unique(samp, it);
  65   VERIFY( it2 == it );
  66 }
  67
  68 void
  69 test03()
  70 {
  71   const int in[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
  72   test_container<const int, input_iterator_wrapper> pop(in);
  73   const int sample_size = 5;
  74   int samp[sample_size] = { };
  75
  76   // input iterator for population
  77   auto it = sample(pop.begin(), pop.end(), samp, sample_size, rng);
  78   VERIFY( it == samp + sample_size );
  79
  80   // verify no duplicates
  81   std::sort(samp, it);
  82   auto it2 = std::unique(samp, it);
  83   VERIFY( it2 == it );
  84 }
  85
  86 void
  87 test04()
  88 {
  89   const int in[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  90   test_container<const int, forward_iterator_wrapper> pop(in);
  91   const int sample_size = 5;
  92   int out[sample_size];
  93   test_container<int, output_iterator_wrapper> samp(out);
  94
  95   // forward iterator for population and output iterator for result
  96   auto res = sample(pop.begin(), pop.end(), samp.begin(), sample_size, rng);
  97
  98   // verify no duplicates
  99   std::sort(std::begin(out), std::end(out));
 100   auto it = std::unique(std::begin(out), std::end(out));
 101   VERIFY( it == std::end(out) );
 102 }
 103
 104 int
 105 main()
 106 {
 107   test01();
 108   test02();
 109   test03();
 110   test04();
 111 }