Compilare: In file included from /usr/include/c++/12.2.1/deque:64, from main.cpp:4: In copy constructor 'std::_Deque_iterator<_Tp, _Ref, _Ptr>::_Deque_iterator(const std::_Deque_iterator<_Tp, _Ref, _Ptr>&) [with _Tp = Node*; _Ref = Node*&; _Ptr = Node**]', inlined from 'std::deque<_Tp, _Alloc>::iterator std::deque<_Tp, _Alloc>::begin() [with _Tp = Node*; _Alloc = std::allocator<Node*>]' at /usr/include/c++/12.2.1/bits/stl_deque.h:1152:30, inlined from 'std::deque<_Tp, _Alloc>::reference std::deque<_Tp, _Alloc>::front() [with _Tp = Node*; _Alloc = std::allocator<Node*>]' at /usr/include/c++/12.2.1/bits/stl_deque.h:1447:9, inlined from 'Node* HuffmanCoder::dequeue_min_weight_node()' at main.cpp:73:49, inlined from 'void HuffmanCoder::build_prefix_code_tree()' at main.cpp:82:56: /usr/include/c++/12.2.1/bits/stl_deque.h:169:21: warning: 'deque_ptr' may be used uninitialized [-Wmaybe-uninitialized] 169 | : _M_cur(__x._M_cur), _M_first(__x._M_first), | ~~~~^~~~~~ main.cpp: In member function 'void HuffmanCoder::build_prefix_code_tree()': main.cpp:61:28: note: 'deque_ptr' was declared here 61 | std::deque<Node*>* deque_ptr; | ^~~~~~~~~ In member function 'void std::deque<_Tp, _Alloc>::pop_front() [with _Tp = Node*; _Alloc = std::allocator<Node*>]', inlined from 'Node* HuffmanCoder::dequeue_min_weight_node()' at main.cpp:74:29, inlined from 'void HuffmanCoder::build_prefix_code_tree()' at main.cpp:81:55: /usr/include/c++/12.2.1/bits/stl_deque.h:1578:39: warning: 'deque_ptr' may be used uninitialized [-Wmaybe-uninitialized] 1578 | != this->_M_impl._M_start._M_last - 1) | ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~ main.cpp: In member function 'void HuffmanCoder::build_prefix_code_tree()': main.cpp:61:28: note: 'deque_ptr' was declared here 61 | std::deque<Node*>* deque_ptr; | ^~~~~~~~~