Compilare: user.cpp: In function ‘void init()’: user.cpp:86:66: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0, x = id; x != 0 && j < relatii[x].size(); x = relatii[x][j] , ++j) ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:29:47: 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:51:51: 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); ^