Compilare: main.cpp: In function 'int _delete(int, Node*, std::string&)': main.cpp:33:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 33 | if(i == s.size()) | ~~^~~~~~~~~~~ main.cpp: In function 'int _occurences(std::string&)': main.cpp:49:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | for(int i = 0; i < s.size(); i++) | ~~^~~~~~~~~~ main.cpp: In function 'int _prefix(std::string&)': main.cpp:58:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 58 | for(i = 0; i < s.size(); i++) | ~~^~~~~~~~~~ main.cpp:57:12: warning: unused variable 'lg' [-Wunused-variable] 57 | int i, lg = 0; | ^~