Compilare: user.cpp: In function ‘int main()’: user.cpp:83:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] str[i] = C[str[i]]; ^ user.cpp:109:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] ++cnt[index][str[j]]; ^ user.cpp:112:38: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (cnt[index][str[j]] > cnt[index][max_index[index]]) ^ user.cpp:77:18: warning: unused variable ‘k’ [-Wunused-variable] int d, i, j, k; ^ user.cpp:126:10: warning: unused variable ‘line’ [-Wunused-variable] char line[20]; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:17:48: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:57:52: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^