Compilare: main.cpp: In function 'void prefix()': main.cpp:13:19: 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=1; i<s.size(); i++) { | ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:32:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 32 | for(int i=0; i<s.size(); i++) { | ~^~~~~~~~~