Compilare: main.cpp: In function 'int main()': main.cpp:29:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 29 | for(int j=0; j<x.size(); j++) | ~^~~~~~~~~ main.cpp:45:18: warning: variable 'ok' set but not used [-Wunused-but-set-variable] 45 | bool ok=0; | ^~