Compilare: main.cpp: In function 'int main()': main.cpp:24:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 24 | for(int i=0;i<s.size();i++) | ~^~~~~~~~~ main.cpp:37:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | if(last==s.size()) | ~~~~^~~~~~~~~~