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

   1 // Copyright (C) 2014-2024 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-do run { target c++17 } }
  19 // { dg-require-cstdint "" }
  20
  21 #include <algorithm>
  22 #include <random>
  23 #include <testsuite_hooks.h>
  24 #include <testsuite_iterators.h>
  25
  26 std::mt19937 rng;
  27
  28 using std::sample;
  29 using __gnu_test::test_container;
  30 using __gnu_test::input_iterator_wrapper;
  31 using __gnu_test::output_iterator_wrapper;
  32 using __gnu_test::forward_iterator_wrapper;
  33 using __gnu_test::random_access_iterator_wrapper;
  34
  35 void
  36 test01()
  37 {
  38   const int in[] = { 1, 2 };
  39   test_container<const int, random_access_iterator_wrapper> pop(in);
  40   const int sample_size = 10;
  41   int samp[sample_size] = { };
  42
  43   // population smaller than desired sample size
  44   auto it = sample(pop.begin(), pop.end(), samp, sample_size, rng);
  45   VERIFY( it == samp + std::distance(pop.begin(), pop.end()) );
  46   const auto sum = std::accumulate(pop.begin(), pop.end(), 0);
  47   VERIFY( std::accumulate(samp, samp + sample_size, 0) == sum );
  48 }
  49
  50 void
  51 test02()
  52 {
  53   const int in[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
  54   test_container<const int, random_access_iterator_wrapper> pop(in);
  55   const int sample_size = 10;
  56   int samp[sample_size] = { };
  57
  58   auto it = sample(pop.begin(), pop.end(), samp, sample_size, rng);
  59   VERIFY( it == samp + sample_size );
  60
  61   // verify no duplicates
  62   std::sort(samp, it);
  63   auto it2 = std::unique(samp, it);
  64   VERIFY( it2 == it );
  65 }
  66
  67 void
  68 test03()
  69 {
  70   const int in[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
  71   test_container<const int, input_iterator_wrapper> pop(in);
  72   const int sample_size = 5;
  73   int samp[sample_size] = { };
  74
  75   // input iterator for population
  76   auto it = sample(pop.begin(), pop.end(), samp, sample_size, rng);
  77   VERIFY( it == samp + sample_size );
  78
  79   // verify no duplicates
  80   std::sort(samp, it);
  81   auto it2 = std::unique(samp, it);
  82   VERIFY( it2 == it );
  83 }
  84
  85 void
  86 test04()
  87 {
  88   const int in[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  89   test_container<const int, forward_iterator_wrapper> pop(in);
  90   const int sample_size = 5;
  91   int out[sample_size];
  92   test_container<int, output_iterator_wrapper> samp(out);
  93
  94   // forward iterator for population and output iterator for result
  95   auto res = sample(pop.begin(), pop.end(), samp.begin(), sample_size, rng);
  96   VERIFY( res.ptr == (out + sample_size) );
  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 }