Compilare: main.cpp: In function 'int main()': main.cpp:14:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 14 | for (int j=0; j<s.size(); ++j) | ~^~~~~~~~~ main.cpp:19:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 19 | for (int j=0; j<s.size(); ++j) | ~^~~~~~~~~