Compilare: main.cpp: In function 'int main()': main.cpp:52:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 52 | for(int i = 1; i<=s.size(); i++) | ~^~~~~~~~~~ main.cpp:58:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 58 | for(int i = 0; i<s.size(); i++) | ~^~~~~~~~~