Compilare: main.cpp: In function 'void add(Tnode*, std::string, int)': main.cpp:23:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 23 | if(i == s.size()){ | ~~^~~~~~~~~~~ main.cpp:28:22: warning: array subscript has type 'char' [-Wchar-subscripts] 28 | int ind = fr[s[i]]; | ^ main.cpp: In function 'bool del(Tnode*, std::string, int)': main.cpp:37:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | if(i == s.size()) | ~~^~~~~~~~~~~ main.cpp:48:22: warning: array subscript has type 'char' [-Wchar-subscripts] 48 | int ind = fr[s[i]]; | ^ main.cpp: In function 'int num_word(Tnode*, std::string, int)': main.cpp:67:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 67 | if(i == s.size()) | ~~^~~~~~~~~~~ main.cpp:70:22: warning: array subscript has type 'char' [-Wchar-subscripts] 70 | int ind = fr[s[i]]; | ^ main.cpp: In function 'int find_pref(Tnode*, std::string, int)': main.cpp:79:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 79 | if(i == s.size()) | ~~^~~~~~~~~~~ main.cpp:82:22: warning: array subscript has type 'char' [-Wchar-subscripts] 82 | int ind = fr[s[i]]; | ^