Compilare: main.cpp: In function 'int main()': main.cpp:95:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 95 | for (i = 0; i < s.length(); ++i) | ~~^~~~~~~~~~~~ main.cpp:103:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 103 | while (i < s.length()) | ~~^~~~~~~~~~~~