Compilare: user.cpp: In function ‘int main()’: user.cpp:33:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!ap[str[i + j]]) ^ user.cpp:34:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[str[i+j]]++; ^ user.cpp:35:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] ap[str[i + j]] = true; ^ user.cpp:13:27: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(str, MAX_S+1, fin); ^