尝试编译我的HuffmanNode类以进行分配时遇到以下错误，这似乎与该类中的shared_ptrs有关，但是我不知道由于纯粹的原因实际出了什么问题我似乎找不到实际问题的大量文本。
g++ -std=c++11 -c src/HuffmanNode.cpp -o obj/HuffmanNode.o -I headers
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/c++allocator.h:33:0,
from /usr/include/c++/7/bits/allocator.h:46,
from /usr/include/c++/7/memory:63,
from headers/HuffmanNode.hpp:9,
from src/HuffmanNode.cpp:5:
/usr/include/c++/7/ext/new_allocator.h: In instantiation of ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = FLNRHE001::HuffmanNode; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode]’:
/usr/include/c++/7/bits/alloc_traits.h:475:4: required from ‘static void std::allocator_traits<std::allocator<_Tp1> >::construct(std::allocator_traits<std::allocator<_Tp1> >::allocator_type&, _Up*, _Args&& ...) [with _Up = FLNRHE001::HuffmanNode; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode; std::allocator_traits<std::allocator<_Tp1> >::allocator_type = std::allocator<FLNRHE001::HuffmanNode>]’
/usr/include/c++/7/bits/shared_ptr_base.h:526:39: required from ‘std::_Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp>::_Sp_counted_ptr_inplace(_Alloc, _Args&& ...) [with _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode; _Alloc = std::allocator<FLNRHE001::HuffmanNode>; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2]’
/usr/include/c++/7/bits/shared_ptr_base.h:637:4: required from ‘std::__shared_count<_Lp>::__shared_count(std::_Sp_make_shared_tag, _Tp*, const _Alloc&, _Args&& ...) [with _Tp = FLNRHE001::HuffmanNode; _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2]’
/usr/include/c++/7/bits/shared_ptr_base.h:1295:35: required from ‘std::__shared_ptr<_Tp, _Lp>::__shared_ptr(std::_Sp_make_shared_tag, const _Alloc&, _Args&& ...) [with _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2]’
/usr/include/c++/7/bits/shared_ptr.h:344:64: required from ‘std::shared_ptr<_Tp>::shared_ptr(std::_Sp_make_shared_tag, const _Alloc&, _Args&& ...) [with _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode]’
/usr/include/c++/7/bits/shared_ptr.h:690:14: required from ‘std::shared_ptr<_Tp> std::allocate_shared(const _Alloc&, _Args&& ...) [with _Tp = FLNRHE001::HuffmanNode; _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}]’
/usr/include/c++/7/bits/shared_ptr.h:706:39: required from ‘std::shared_ptr<_Tp> std::make_shared(_Args&& ...) [with _Tp = FLNRHE001::HuffmanNode; _Args = {const std::shared_ptr<FLNRHE001::HuffmanNode>&}]’
src/HuffmanNode.cpp:34:72: required from here
/usr/include/c++/7/ext/new_allocator.h:136:4: error: no matching function for call to ‘FLNRHE001::HuffmanNode::HuffmanNode(const std::shared_ptr<FLNRHE001::HuffmanNode>&)’
{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/HuffmanNode.cpp:41:1: note: candidate: FLNRHE001::HuffmanNode::HuffmanNode(FLNRHE001::HuffmanNode&&)
HuffmanNode::HuffmanNode(HuffmanNode &&n)
^~~~~~~~~~~
src/HuffmanNode.cpp:41:1: note: no known conversion for argument 1 from ‘const std::shared_ptr<FLNRHE001::HuffmanNode>’ to ‘FLNRHE001::HuffmanNode&&’
src/HuffmanNode.cpp:33:1: note: candidate: FLNRHE001::HuffmanNode::HuffmanNode(const FLNRHE001::HuffmanNode&)
HuffmanNode::HuffmanNode(const HuffmanNode &n)
^~~~~~~~~~~
src/HuffmanNode.cpp:33:1: note: no known conversion for argument 1 from ‘const std::shared_ptr<FLNRHE001::HuffmanNode>’ to ‘const FLNRHE001::HuffmanNode&’
src/HuffmanNode.cpp:11:1: note: candidate: FLNRHE001::HuffmanNode::HuffmanNode(char, int, std::shared_ptr<FLNRHE001::HuffmanNode>, std::shared_ptr<FLNRHE001::HuffmanNode>)
HuffmanNode::HuffmanNode(char c, int f, std::shared_ptr<HuffmanNode> l, std::shared_ptr<HuffmanNode> r)
^~~~~~~~~~~
src/HuffmanNode.cpp:11:1: note: candidate expects 4 arguments, 1 provided
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/c++allocator.h:33:0,
from /usr/include/c++/7/bits/allocator.h:46,
from /usr/include/c++/7/memory:63,
from headers/HuffmanNode.hpp:9,
from src/HuffmanNode.cpp:5:
/usr/include/c++/7/ext/new_allocator.h: In instantiation of ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = FLNRHE001::HuffmanNode; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp
= FLNRHE001::HuffmanNode]’:
/usr/include/c++/7/bits/alloc_traits.h:475:4: required from ‘static void std::allocator_traits<std::allocator<_Tp1> >::construct(std::allocator_traits<std::allocator<_Tp1> >::allocator_type&, _Up*, _Args&& ...) [with _Up = FLNRHE001::HuffmanNode; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode; std::allocator_traits<std::allocator<_Tp1> >::allocator_type = std::allocator<FLNRHE001::HuffmanNode>]’
/usr/include/c++/7/bits/shared_ptr_base.h:526:39: required from ‘std::_Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp>::_Sp_counted_ptr_inplace(_Alloc, _Args&& ...) [with _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&};
_Tp = FLNRHE001::HuffmanNode; _Alloc = std::allocator<FLNRHE001::HuffmanNode>; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2]’
/usr/include/c++/7/bits/shared_ptr_base.h:637:4: required from ‘std::__shared_count<_Lp>::__shared_count(std::_Sp_make_shared_tag, _Tp*, const _Alloc&, _Args&& ...) [with _Tp = FLNRHE001::HuffmanNode; _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2]’
/usr/include/c++/7/bits/shared_ptr_base.h:1295:35: required from ‘std::__shared_ptr<_Tp, _Lp>::__shared_ptr(std::_Sp_make_shared_tag, const _Alloc&, _Args&& ...) [with _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode; __gnu_cxx::_Lock_policy _Lp = (__gnu_cxx::_Lock_policy)2]’
/usr/include/c++/7/bits/shared_ptr.h:344:64: required from ‘std::shared_ptr<_Tp>::shared_ptr(std::_Sp_make_shared_tag, const _Alloc&, _Args&& ...) [with _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}; _Tp = FLNRHE001::HuffmanNode]’
/usr/include/c++/7/bits/shared_ptr.h:690:14: required from ‘std::shared_ptr<_Tp> std::allocate_shared(const _Alloc&, _Args&& ...) [with _Tp = FLNRHE001::HuffmanNode; _Alloc = std::allocator<FLNRHE001::HuffmanNode>; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}]’
/usr/include/c++/7/bits/shared_ptr.h:706:39: required from ‘std::shared_ptr<_Tp> std::make_shared(_Args&& ...) [with _Tp = FLNRHE001::HuffmanNode; _Args = {std::shared_ptr<FLNRHE001::HuffmanNode>&}]’
src/HuffmanNode.cpp:93:52: required from here
/usr/include/c++/7/ext/new_allocator.h:136:4: error: no matching function for call to ‘FLNRHE001::HuffmanNode::HuffmanNode(std::shared_ptr<FLNRHE001::HuffmanNode>&)’
{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/HuffmanNode.cpp:41:1: note: candidate: FLNRHE001::HuffmanNode::HuffmanNode(FLNRHE001::HuffmanNode&&)
HuffmanNode::HuffmanNode(HuffmanNode &&n)
^~~~~~~~~~~
src/HuffmanNode.cpp:41:1: note: no known conversion for argument 1 from ‘std::shared_ptr<FLNRHE001::HuffmanNode>’ to ‘FLNRHE001::HuffmanNode&&’
src/HuffmanNode.cpp:33:1: note: candidate: FLNRHE001::HuffmanNode::HuffmanNode(const FLNRHE001::HuffmanNode&)
HuffmanNode::HuffmanNode(const HuffmanNode &n)
^~~~~~~~~~~
src/HuffmanNode.cpp:33:1: note: no known conversion for argument 1 from ‘std::shared_ptr<FLNRHE001::HuffmanNode>’ to ‘const FLNRHE001::HuffmanNode&’
src/HuffmanNode.cpp:11:1: note: candidate: FLNRHE001::HuffmanNode::HuffmanNode(char, int, std::shared_ptr<FLNRHE001::HuffmanNode>, std::shared_ptr<FLNRHE001::HuffmanNode>)
HuffmanNode::HuffmanNode(char c, int f, std::shared_ptr<HuffmanNode> l, std::shared_ptr<HuffmanNode> r)
^~~~~~~~~~~
src/HuffmanNode.cpp:11:1: note: candidate expects 4 arguments, 1 provided
我尝试查找错误，但似乎找不到能解决问题的任何东西。
由于它是一个赋值，所以我无法发布整个代码，但是错误文本中提到的行是我的构造函数声明，如上所述，问题似乎出在shared_ptrs上：
line 11: HuffmanNode::HuffmanNode(char c, int f, std::shared_ptr<HuffmanNode> l, std::shared_ptr<HuffmanNode> r)
line 33: HuffmanNode::HuffmanNode(const HuffmanNode &n) : ch(n.ch), freq(n.freq), left(std::make_shared<HuffmanNode>(n.left)), right(std::make_shared<HuffmanNode>(n.right))
line 41: HuffmanNode::HuffmanNode(HuffmanNode &&n) : ch(std::move(n.ch)), freq(std::move(n.freq)), left(std::move(n.left)), right(std::move(n.right))
编辑：
这是我可以根据学校规定发布的内容，问题区域内唯一包含任何内容的方法是move构造函数，这只是确保在调用析构函数时不会出现重复删除错误。这给了我与上面相同的错误。
#include <memory>
class HuffmanNode
{
char ch;
int freq;
std::shared_ptr<HuffmanNode> left, right;
// Node constructor for leaf node
HuffmanNode(char c, int f, std::shared_ptr<HuffmanNode> l, std::shared_ptr<HuffmanNode> r)
: ch(c), freq(f), left(l), right(r)
{
// Handled in initialiser list
}
HuffmanNode(const HuffmanNode &n)
: ch(n.ch), freq(n.freq), left(std::make_shared<HuffmanNode>(n.left)),
right(std::make_shared<HuffmanNode>(n.right))
{
// Handled by initialiser list
}
// Move Constructor
HuffmanNode(HuffmanNode &&n)
: ch(std::move(n.ch)), freq(std::move(n.freq)),
left(std::move(n.left)),
right(std::move(n.right))
{
}
};
答案 0 :(得分：0)
错误是由于尝试使用make_shared创建左右指针的副本而引起的，在这种情况下，我只需要shared_ptr副本构造函数制作的浅表副本。 / p>
更正后的解决方案仅是对move构造函数的更改，如下所示：
HuffmanNode(const HuffmanNode &n)
: ch(n.ch), freq(n.freq), left(n.left),
right(n.right)
{
// Handled by initialiser list
}
感谢Sam Varshavchik在此方面的帮助！