Compilare: main.cpp: In function 'int main()': main.cpp:87:51: warning: comparison of integer expressions of different signedness: 'unsigned int' and 'int' [-Wsign-compare] 87 | while (IT != prime.end() && (*IT) <= n && n != 1) { | ~~~~~~^~~~ In file included from /usr/include/c++/12.2.1/vector:65, from main.cpp:2: In member function 'constexpr void std::_Bvector_base<_Alloc>::_M_deallocate() [with _Alloc = std::allocator<bool>]', inlined from 'constexpr std::_Bvector_base<_Alloc>::~_Bvector_base() [with _Alloc = std::allocator<bool>]' at /usr/include/c++/12.2.1/bits/stl_bvector.h:622:28, inlined from 'constexpr std::vector<bool, _Alloc>::~vector() [with _Alloc = std::allocator<bool>]' at /usr/include/c++/12.2.1/bits/stl_bvector.h:839:37, inlined from 'void init_sieve()' at main.cpp:43:1: /usr/include/c++/12.2.1/bits/stl_bvector.h:647:30: warning: 'ciur.std::vector<bool, std::allocator<bool> >::<unnamed>.std::_Bvector_base<std::allocator<bool> >::_M_impl.std::_Bvector_base<std::allocator<bool> >::_Bvector_impl::<anonymous>.std::_Bvector_base<std::allocator<bool> >::_Bvector_impl_data::_M_start.std::_Bit_iterator::<anonymous>.std::_Bit_iterator_base::_M_p' may be used uninitialized [-Wmaybe-uninitialized] 647 | if (_M_impl._M_start._M_p) | ~~~~~~~~~~~~~~~~~^~~~ main.cpp: In function 'void init_sieve()': main.cpp:27:27: note: 'ciur' declared here 27 | std::vector<bool> ciur(MIL, false); | ^~~~ In member function 'constexpr std::_Bit_type* std::_Bvector_base<_Alloc>::_Bvector_impl::_M_end_addr() const [with _Alloc = std::allocator<bool>]', inlined from 'constexpr void std::_Bvector_base<_Alloc>::_M_deallocate() [with _Alloc = std::allocator<bool>]' at /usr/include/c++/12.2.1/bits/stl_bvector.h:649:44, inlined from 'constexpr std::_Bvector_base<_Alloc>::~_Bvector_base() [with _Alloc = std::allocator<bool>]' at /usr/include/c++/12.2.1/bits/stl_bvector.h:622:28, inlined from 'constexpr std::vector<bool, _Alloc>::~vector() [with _Alloc = std::allocator<bool>]' at /usr/include/c++/12.2.1/bits/stl_bvector.h:839:37, inlined from 'void init_sieve()' at main.cpp:43:1: /usr/include/c++/12.2.1/bits/stl_bvector.h:577:21: warning: 'ciur.std::vector<bool, std::allocator<bool> >::<unnamed>.std::_Bvector_base<std::allocator<bool> >::_M_impl.std::_Bvector_base<std::allocator<bool> >::_Bvector_impl::<anonymous>.std::_Bvector_base<std::allocator<bool> >::_Bvector_impl_data::_M_end_of_storage' may be used uninitialized [-Wmaybe-uninitialized] 577 | if (this->_M_end_of_storage) | ~~~~~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'void init_sieve()': main.cpp:27:27: note: 'ciur' declared here 27 | std::vector<bool> ciur(MIL, false); | ^~~~