Compilare: user.cpp: In function ‘void prec_()’: user.cpp:41:9: warning: array subscript has type ‘char’ [-Wchar-subscripts] ok[a] = ok[a ^ 0x20] = 1; ^ user.cpp:43:9: warning: array subscript has type ‘char’ [-Wchar-subscripts] ok[a] = 1; ^ user.cpp: In function ‘void input()’: user.cpp:51:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (; ok[*cur]; ++cur); ^ user.cpp:53:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (; !ok[*cur]; ++cur); ^ user.cpp: In function ‘int main()’: user.cpp:61:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(InFile, "r", stdin); ^ user.cpp:62:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(OuFile, "w", stdout); ^