libstdc++-v3/testsuite/24_iterators/common_iterator/2.cc

   1 // Copyright (C) 2020-2021 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++2a" }
  19 // { dg-do run { target c++2a } }
  20
  21 #include <iterator>
  22 #include <testsuite_hooks.h>
  23
  24 struct value { int n; };
  25
  26 struct sentinel { int limit; };
  27
  28 struct iterator
  29 {
  30   using iterator_category = std::input_iterator_tag;
  31   using value_type = value;
  32   using difference_type = std::ptrdiff_t;
  33   using reference = value;
  34
  35   value operator*() const { return value{counter}; }
  36
  37   iterator& operator++() { ++counter; return *this; }
  38
  39   iterator operator++(int) { auto i = *this; ++counter; return i; }
  40
  41   bool operator==(sentinel s) const { return counter == s.limit; }
  42
  43   int counter = 0;
  44 };
  45
  46 void
  47 test01()
  48 {
  49   iterator i;
  50   sentinel s{2};
  51   std::common_iterator<iterator, sentinel> begin = i, end = s;
  52   VERIFY( begin->n == 0 );
  53   ++begin;
  54   VERIFY( begin->n == 1 );
  55   ++begin;
  56   VERIFY( begin == end );
  57 }
  58
  59 int
  60 main()
  61 {
  62   test01();
  63 }