Compilare: main.cpp: In function 'int main()': main.cpp:18:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 18 | for (i = 0 ; i < s.size(); i++) | ~~^~~~~~~~~~ main.cpp:15:15: warning: unused variable 'y' [-Wunused-variable] 15 | int i, x, y; | ^