Compilare: main.cpp: In function 'void add(node*, std::string, int)': main.cpp:28:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 28 | if(s.size() == pos) | ~~~~~~~~~^~~~~~ main.cpp: In function 'void del(node*, std::string, int)': main.cpp:49:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 49 | if(s.size() == pos) | ~~~~~~~~~^~~~~~ main.cpp: In function 'int count(node*, std::string, int)': main.cpp:72:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 72 | if(s.size() == pos) | ~~~~~~~~~^~~~~~ main.cpp: In function 'int pref(node*, std::string, int)': main.cpp:86:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 86 | if(s.size() == pos) | ~~~~~~~~~^~~~~~