Compilare: user.cpp: In function ‘int main()’: user.cpp:89:56: warning: statement has no effect [-Wunused-value] Dp[ (xx << 12) + (yy << 3) + dir ] > Dp[ (xx << 12) + (yy << 3) + dd ] + abs(p); ^ user.cpp: In member function ‘void input_reader::advance()’: user.cpp:23:53: 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 constructor ‘input_reader::input_reader(const char*, const char*)’: user.cpp:35:49: 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 ); ^