libstdc++-v3/testsuite/23_containers/unordered_set/erasure.cc

   1 // { dg-do run { target c++20 } }
   2 // { dg-add-options no_pch }
   3
   4 // Copyright (C) 2018-2025 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <unordered_set>
  22
  23 #ifndef __cpp_lib_erase_if
  24 # error "Feature-test macro for erase_if missing in <unordered_set>"
  25 #elif __cpp_lib_erase_if < 202002
  26 # error "Feature-test macro for erase_if has wrong value in <unordered_set>"
  27 #endif
  28
  29 #include <testsuite_hooks.h>
  30
  31 void
  32 test01()
  33 {
  34   auto is_odd = [](const int i) { return i % 2 != 0; };
  35
  36   std::unordered_set<int> us{ 10, 11, 12, 14, 15, 17, 18, 19 };
  37   auto num = std::erase_if(us, is_odd);
  38   std::unordered_set<int> t{ 10, 12, 14, 18 };
  39   VERIFY( us == t );
  40   VERIFY( num == 4 );
  41 }
  42
  43 void
  44 test02()
  45 {
  46   auto is_odd = [](const int i) { return i % 2 != 0; };
  47
  48   std::unordered_multiset<int> ums{ 20, 21, 22, 22, 23, 23, 24, 25 };
  49   auto num = std::erase_if(ums, is_odd);
  50   std::unordered_multiset<int> t{ 20, 22, 22, 24 };
  51   VERIFY( ums == t );
  52   VERIFY( num == 4 );
  53 }
  54
  55 void
  56 test_pr107850()
  57 {
  58   // Predicate only callable as non-const.
  59   struct Pred { bool operator()(const int&) { return false; } };
  60   const Pred pred; // erase_if parameter is passed by value, so non-const.
  61   std::unordered_set<int> s;
  62   std::erase_if(s, pred);
  63   std::unordered_multiset<int> ms;
  64   std::erase_if(ms, pred);
  65 }
  66
  67 int
  68 main()
  69 {
  70   test01();
  71   test02();
  72   test_pr107850();
  73
  74   return 0;
  75 }