Compilare: user.cpp: In function ‘void insert(T*, std::string&)’: user.cpp:27:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] if( n -> chl[chr] == NULL ) { ^ user.cpp:28:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] n -> chl[chr] = new T; } ^ user.cpp:29:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] n = n -> chl[chr]; } ^ user.cpp: In function ‘int count(T*, std::string&)’: user.cpp:57:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] n = n -> chl[ch(chr)]; } ^ user.cpp: In function ‘int main(int, const char**)’: user.cpp:71:49: warning: array subscript has type ‘char’ [-Wchar-subscripts] while( aux != r && aux -> chl[ch(str[i])] == NULL ) { ^ user.cpp:73:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] if( aux -> chl[ch(str[i])] != NULL ) { ^ user.cpp:74:40: warning: array subscript has type ‘char’ [-Wchar-subscripts] aux = aux -> chl[ch(str[i])]; } ^