/in/foo.cc: In function 'int main()':
/in/foo.cc:29:71: warning: operation on 'num' may be undefined [-Wsequence-point]
     while (cin >> day[num++].yue >> a >> day[num].ri >> a >> day[num].nian);
                                                                       ^
/in/foo.cc:35:20: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
     system("pause");
                    ^