Compilare: user.cpp: In function ‘int get_int()’: user.cpp:20:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(; !isDigit[*head]; ++head); ^ user.cpp:22:25: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(; isDigit[*head]; ++head) ^ user.cpp: At global scope: user.cpp:29:37: warning: always_inline function might not be inlinable [-Wattributes] __attribute__((always_inline)) void put_int(int x) ^~~~~~~ user.cpp:16:36: warning: always_inline function might not be inlinable [-Wattributes] __attribute__((always_inline)) int get_int() ^~~~~~~ user.cpp: In function ‘int main()’: user.cpp:93:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in", "r", stdin); ^ user.cpp:94:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.out", "w", stdout); ^