Compilare: user.cpp: In member function ‘InputReader& InputReader::operator>>(int&)’: user.cpp:37:17: warning: variable ‘sign’ set but not used [-Wunused-but-set-variable] int sign = 1; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:30:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:63:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^