libstdc++-v3/testsuite/23_containers/unordered_map/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_map>
  22
  23 #ifndef __cpp_lib_erase_if
  24 # error "Feature-test macro for erase_if missing in <unordered_map>"
  25 #elif __cpp_lib_erase_if < 202002
  26 # error "Feature-test macro for erase_if has wrong value in <unordered_map>"
  27 #endif
  28
  29 #include <string>
  30 #include <testsuite_hooks.h>
  31
  32 auto is_odd_pair = [](const std::pair<const int, std::string>& p)
  33 {
  34   return p.first % 2 != 0;
  35 };
  36
  37 void
  38 test01()
  39 {
  40   std::unordered_map<int, std::string> um{ { 10, "A" }, { 11, "B" },
  41                                            { 12, "C" }, { 14, "D" },
  42                                            { 15, "E" }, { 17, "F" },
  43                                            { 18, "G" }, { 19, "H" } };
  44   auto num = std::erase_if(um, is_odd_pair);
  45   std::unordered_map<int, std::string> t{ { 10, "A" }, { 12, "C" },
  46                                           { 14, "D" }, { 18, "G" } };
  47   VERIFY( um == t );
  48   VERIFY( num == 4 );
  49 }
  50
  51 void
  52 test02()
  53 {
  54   std::unordered_multimap<int, std::string> umm{ { 20, "S" }, { 21, "T" },
  55                                                  { 22, "U" }, { 22, "V" },
  56                                                  { 23, "W" }, { 23, "X" },
  57                                                  { 24, "Y" }, { 25, "Z" } };
  58   auto num = std::erase_if(umm, is_odd_pair);
  59   std::unordered_multimap<int, std::string> t{ { 20, "S" }, { 22, "U" },
  60                                                { 22, "V" }, { 24, "Y" } };
  61   VERIFY( umm == t );
  62   VERIFY( num == 4 );
  63 }
  64
  65 void
  66 test_pr107850()
  67 {
  68   // Predicate only callable as non-const and only accepts non-const argument.
  69   struct Pred { bool operator()(std::pair<const int, int>&) { return false; } };
  70   const Pred pred; // erase_if parameter is passed by value, so non-const.
  71   std::unordered_map<int, int> m;
  72   std::erase_if(m, pred);
  73   std::unordered_multimap<int, int> mm;
  74   std::erase_if(mm, pred);
  75 }
  76
  77 int
  78 main()
  79 {
  80   test01();
  81   test02();
  82   test_pr107850();
  83
  84   return 0;
  85 }