Compilare: In file included from /usr/include/c++/12.2.1/bits/char_traits.h:46, from /usr/include/c++/12.2.1/ios:40, from /usr/include/c++/12.2.1/istream:38, from /usr/include/c++/12.2.1/fstream:38, from main.cpp:1: In function 'constexpr decltype (::new(void*(0)) _Tp) std::construct_at(_Tp*, _Args&& ...) [with _Tp = pair<int, int>; _Args = {pair<int, int>}]', inlined from 'static constexpr void std::allocator_traits<std::allocator<_CharT> >::construct(allocator_type&, _Up*, _Args&& ...) [with _Up = std::pair<int, int>; _Args = {std::pair<int, int>}; _Tp = std::pair<int, int>]' at /usr/include/c++/12.2.1/bits/alloc_traits.h:518:21, inlined from 'constexpr std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {std::pair<int, int>}; _Tp = std::pair<int, int>; _Alloc = std::allocator<std::pair<int, int> >]' at /usr/include/c++/12.2.1/bits/vector.tcc:117:30, inlined from 'int main()' at main.cpp:50:32: /usr/include/c++/12.2.1/bits/stl_construct.h:97:73: warning: 'v' may be used uninitialized [-Wmaybe-uninitialized] 97 | { return ::new((void*)__location) _Tp(std::forward<_Args>(__args)...); } | ^ main.cpp: In function 'int main()': main.cpp:43:13: note: 'v' was declared here 43 | int v; | ^ In function 'constexpr decltype (::new(void*(0)) _Tp) std::construct_at(_Tp*, _Args&& ...) [with _Tp = pair<int, int>; _Args = {pair<int, int>}]', inlined from 'static constexpr void std::allocator_traits<std::allocator<_CharT> >::construct(allocator_type&, _Up*, _Args&& ...) [with _Up = std::pair<int, int>; _Args = {std::pair<int, int>}; _Tp = std::pair<int, int>]' at /usr/include/c++/12.2.1/bits/alloc_traits.h:518:21, inlined from 'constexpr std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {std::pair<int, int>}; _Tp = std::pair<int, int>; _Alloc = std::allocator<std::pair<int, int> >]' at /usr/include/c++/12.2.1/bits/vector.tcc:117:30, inlined from 'int main()' at main.cpp:50:32: /usr/include/c++/12.2.1/bits/stl_construct.h:97:73: warning: 'u' may be used uninitialized [-Wmaybe-uninitialized] 97 | { return ::new((void*)__location) _Tp(std::forward<_Args>(__args)...); } | ^ main.cpp: In function 'int main()': main.cpp:35:13: note: 'u' was declared here 35 | int u; | ^