c++ - 使用自定义比较器声明 C++ 优先级队列的问题

标签 c++ compare priority-queue

我一直在尝试实现一个由自定义数据类型和自定义比较器组成的优先级队列，但是当我尝试编译时出现此错误。我尝试了多个声明，但它们都产生了这个错误。

priority_queue<myData, vector<myData>, myComp> myPQ;

priority_queue<myData, vector<myData>, myComp> myPQ(compVariable);

我也在尝试在创建这些优先级队列后创建它们的 vector 。

   /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h: In instantiation of ‘bool std::less<_Tp>::operator()(const _Tp&, const _Tp&) const [with _Tp = Order]’:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_heap.h:183:47:   required from ‘void std::__push_heap(_RandomAccessIterator, _Distance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Order*, std::vector<Order, std::allocator<Order> > >; _Distance = long int; _Tp = Order; _Compare = std::less<Order>]’
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_heap.h:222:58:   required from ‘void std::push_heap(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Order*, std::vector<Order, std::allocator<Order> > >; _Compare = std::less<Order>]’
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_queue.h:499:41:   required from ‘void std::priority_queue<_Tp, _Sequence, _Compare>::push(const value_type&) [with _Tp = Order; _Sequence = std::vector<Order, std::allocator<Order> >; _Compare = std::less<Order>; std::priority_queue<_Tp, _Sequence, _Compare>::value_type = Order]’
Market.cpp:144:32:   required from here
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: error: no match for ‘operator<’ (operand types are ‘const Order’ and ‘const Order’)
       { return __x < __y; }
                    ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note: candidates are:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_algobase.h:64:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/char_traits.h:39,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_pair.h:220:5: note: template<class _T1, class _T2> constexpr bool std::operator<(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)
     operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_pair.h:220:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::pair<_T1, _T2>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_algobase.h:67:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/char_traits.h:39,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:297:5: note: template<class _Iterator> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&)
     operator<(const reverse_iterator<_Iterator>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:297:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::reverse_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_algobase.h:67:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/char_traits.h:39,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:347:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_IteratorR>&)
     operator<(const reverse_iterator<_IteratorL>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:347:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::reverse_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_algobase.h:67:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/char_traits.h:39,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:1055:5: note: template<class _IteratorL, class _IteratorR> bool std::operator<(const std::move_iterator<_Iterator>&, const std::move_iterator<_IteratorR>&)
     operator<(const move_iterator<_IteratorL>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:1055:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::move_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_algobase.h:67:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/char_traits.h:39,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:1061:5: note: template<class _Iterator> bool std::operator<(const std::move_iterator<_Iterator>&, const std::move_iterator<_Iterator>&)
     operator<(const move_iterator<_Iterator>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_iterator.h:1061:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::move_iterator<_Iterator>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:52:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/basic_string.h:2569:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::basic_string<_CharT, _Traits, _Alloc>&, const std::basic_string<_CharT, _Traits, _Alloc>&)
     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/basic_string.h:2569:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::basic_string<_CharT, _Traits, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:52:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/basic_string.h:2581:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*)
     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/basic_string.h:2581:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::basic_string<_CharT, _Traits, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:52:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/basic_string.h:2593:5: note: template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const _CharT*, const std::basic_string<_CharT, _Traits, _Alloc>&)
     operator<(const _CharT* __lhs,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/basic_string.h:2593:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   mismatched types ‘const _CharT*’ and ‘Order’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/vector:64:0,
                 from P2.h:4,
                 from Market.cpp:3:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_vector.h:1420:5: note: template<class _Tp, class _Alloc> bool std::operator<(const std::vector<_Tp, _Alloc>&, const std::vector<_Tp, _Alloc>&)
     operator<(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_vector.h:1420:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::vector<_Tp, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/deque:64:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/queue:60,
                 from Market.cpp:6:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_deque.h:273:5: note: template<class _Tp, class _Ref, class _Ptr> bool std::operator<(const std::_Deque_iterator<_Tp, _Ref, _Ptr>&, const std::_Deque_iterator<_Tp, _Ref, _Ptr>&)
     operator<(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_deque.h:273:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::_Deque_iterator<_Tp, _Ref, _Ptr>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/deque:64:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/queue:60,
                 from Market.cpp:6:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_deque.h:281:5: note: template<class _Tp, class _RefL, class _PtrL, class _RefR, class _PtrR> bool std::operator<(const std::_Deque_iterator<_Tp, _Ref, _Ptr>&, const std::_Deque_iterator<_Tp, _RefR, _PtrR>&)
     operator<(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_deque.h:281:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::_Deque_iterator<_Tp, _Ref, _Ptr>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/deque:64:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/queue:60,
                 from Market.cpp:6:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_deque.h:1975:5: note: template<class _Tp, class _Alloc> bool std::operator<(const std::deque<_Tp, _Alloc>&, const std::deque<_Tp, _Alloc>&)
     operator<(const deque<_Tp, _Alloc>& __x,
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_deque.h:1975:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::deque<_Tp, _Alloc>’
       { return __x < __y; }
                    ^
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/queue:64:0,
                 from Market.cpp:6:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_queue.h:286:5: note: template<class _Tp, class _Seq> bool std::operator<(const std::queue<_Tp, _Seq>&, const std::queue<_Tp, _Seq>&)
     operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
     ^
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_queue.h:286:5: note:   template argument deduction/substitution failed:
In file included from /usr/um/gcc-4.8.2/include/c++/4.8.2/string:48:0,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/locale_classes.h:40,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/bits/ios_base.h:41,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ios:42,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/ostream:38,
                 from /usr/um/gcc-4.8.2/include/c++/4.8.2/iostream:39,
                 from Market.cpp:1:
/usr/um/gcc-4.8.2/include/c++/4.8.2/bits/stl_function.h:235:20: note:   ‘const Order’ is not derived from ‘const std::queue<_Tp, _Seq>’
       { return __x < __y; }

这是导致错误的示例:

class myData {
public:
    int a;
    int b;
    int c;
    int d;
};

class myComp {
public:
    bool operator()(myData& d1, myData& d2) {
        if(d1.a == d2.a) {
            return d2.b < d2.c;
        }
        else {
            return d1.a < d2.a;
        }
    }
};

priority_queue<myData, vector<myData>, myComp> myPQ;

vector<priority_queue<myData, vector<myData>, myComp> > vec_PQ(n, myPQ);

最佳答案

发件人:http://en.cppreference.com/w/cpp/concept/Compare

The concept Compare is a set of requirements expected by some of the standard library facilities from the user-provided function object types.

The return value of the function call operation applied to an object of type Compare, when contextually converted to bool, yields true if the first argument of the call appears before the second in the strict weak ordering relation induced by this Compare type, and false otherwise.

As with any BinaryPredicate, evaluation of that expression is not allowed to call non-const member functions of the dereferenced iterators.

myComp::operator() 的参数应该是const&。

bool myComp::operator()(myData const& d1, myData const& d2) {

如@T.C 所示。在注释中，函数本身应该是一个 const 成员函数，但在这种情况下完全没有必要。

关于c++ - 使用自定义比较器声明 C++ 优先级队列的问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28909261/

上一篇：c++ - 如何关联通过抽象工厂创建的不相关对象

下一篇：具有常量值的 C++ Boost ptr_map

相关文章：

c++ - new(size) 和 new[size] 的区别

c++ - 如何做 #define macro to do #define "myInt x" "int* x = new int[5]"

比较两个不同类型的数组

c++ - 复制STL:删除元素，用户定义的函数作为参数和事件队列

c++ - 如何在Xcode项目中使用dlib face_recognition？

c++ - 在 Cocos2d-x 中存储屏幕大小、原点和其他全局变量的有效方法？

c++ - 检查小数点后第 n 位的精度？

python - 如何比较字典列表中的多个键值？

r - R 中用于 OPTICS 实现的优先级队列

java - poll() 返回类型与 PriorityBlockingQueue.poll() 冲突

©2024 IT工具网  联系我们