Compilare: main.cpp: In function 'int main()': main.cpp:20:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 20 | if (s[i].size()>mx){ | ~~~~~~~~~~~^~~ main.cpp:24:33: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 24 | else if (s[i].size()==mx){ | ~~~~~~~~~~~^~~~ main.cpp:37:36: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for (int b=0; b<s[j].size() && a<s[i].size(); b++) | ~^~~~~~~~~~~~ main.cpp:37:53: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for (int b=0; b<s[j].size() && a<s[i].size(); b++) | ~^~~~~~~~~~~~ main.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 40 | if (a==s[i].size()) | ~^~~~~~~~~~~~~ In file included from /usr/include/c++/12.2.1/string:53, from /usr/include/c++/12.2.1/bits/locale_classes.h:40, from /usr/include/c++/12.2.1/bits/ios_base.h:41, from /usr/include/c++/12.2.1/ios:42, from /usr/include/c++/12.2.1/ostream:38, from /usr/include/c++/12.2.1/iostream:39, from main.cpp:1: In member function 'constexpr std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::pointer std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_data() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]', inlined from 'constexpr const _CharT* std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::data() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /usr/include/c++/12.2.1/bits/basic_string.h:2568:23, inlined from 'std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&) [with _CharT = char; _Traits = char_traits<char>; _Alloc = allocator<char>]' at /usr/include/c++/12.2.1/bits/basic_string.h:3888:30, inlined from 'int main()' at main.cpp:29:18: /usr/include/c++/12.2.1/bits/basic_string.h:234:28: warning: 'j' may be used uninitialized [-Wmaybe-uninitialized] 234 | { return _M_dataplus._M_p; } | ^~~~ main.cpp: In function 'int main()': main.cpp:18:19: note: 'j' was declared here 18 | int mx=0, j; | ^