Compilare: main.cpp: In function 'int main()': main.cpp:13:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | for(int i=0;i<s.size();i++) | ~^~~~~~~~~ main.cpp:10:9: warning: unused variable 'a' [-Wunused-variable] 10 | int a,ok=0,p=0; | ^ main.cpp:10:11: warning: variable 'ok' set but not used [-Wunused-but-set-variable] 10 | int a,ok=0,p=0; | ^~