Compilare: main.cpp: In function 'int ec(int&)': main.cpp:20:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | while (i < s.length() && isdigit(s[i])) | ~~^~~~~~~~~~~~ main.cpp:24:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 24 | while (i < s.length()) | ~~^~~~~~~~~~~~ main.cpp:34:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 34 | while (i < s.length() && isdigit(s[i])) | ~~^~~~~~~~~~~~