libstdc++-v3/testsuite/20_util/optional/assignment/5.cc

   1 // { dg-options "-std=gnu++17" }
   2 // { dg-do run { target c++17 }  }
   3
   4 // Copyright (C) 2013-2019 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 <optional>
  22 #include <vector>
  23 #include <testsuite_hooks.h>
  24
  25 int counter = 0;
  26
  27 struct mixin_counter
  28 {
  29   mixin_counter() { ++counter; }
  30   mixin_counter(mixin_counter const&) { ++counter; }
  31   ~mixin_counter() { --counter; }
  32 };
  33
  34 struct value_type : private mixin_counter { };
  35
  36 int main()
  37 {
  38   using O = std::optional<value_type>;
  39
  40   // Check std::nullopt_t and 'default' (= {}) assignment
  41
  42   {
  43     O o;
  44     o = std::nullopt;
  45     VERIFY( !o );
  46   }
  47
  48   {
  49     O o { std::in_place };
  50     o = std::nullopt;
  51     VERIFY( !o );
  52   }
  53
  54   {
  55     O o;
  56     o = {};
  57     VERIFY( !o );
  58   }
  59
  60   {
  61     O o { std::in_place };
  62     o = {};
  63     VERIFY( !o );
  64   }
  65   {
  66     std::optional<std::vector<int>> ovi{{1, 2, 3}};
  67     VERIFY(ovi->size() == 3);
  68     VERIFY((*ovi)[0] == 1 && (*ovi)[1] == 2 && (*ovi)[2] == 3);
  69     ovi = {4, 5, 6, 7};
  70     VERIFY(ovi->size() == 4);
  71     VERIFY((*ovi)[0] == 4 && (*ovi)[1] == 5 &&
  72            (*ovi)[2] == 6 && (*ovi)[3] == 7);
  73   }
  74   VERIFY( counter == 0 );
  75 }