Compilare: user.cpp: In function ‘int pref(trie*, char*, int)’: user.cpp:80:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(root->m[a] == 0 || root->m[a]->cnt == 0) { ^ user.cpp:80:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(root->m[a] == 0 || root->m[a]->cnt == 0) { ^ user.cpp:83:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] return pref(root->m[a], c+1, crr+1); ^ user.cpp: In function ‘int main()’: user.cpp:92:9: warning: unused variable ‘t’ [-Wunused-variable] int t; ^ user.cpp:93:11: warning: unused variable ‘wa’ [-Wunused-variable] char *wa; ^ user.cpp:96:23: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(x, MAX, fin); ^ user.cpp:109:27: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(x, MAX, fin); ^