Compilare: main.cpp: In function 'int main()': main.cpp:12:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 12 | for (int i=0; i<s2.size(); i++) | ~^~~~~~~~~~ main.cpp:20:26: warning: unused variable 'mirror' [-Wunused-variable] 20 | int center=0,right=0,mirror; | ^~~~~~