foo.c: In function 'main':
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",num);
  ^~~~~~~~~~~~~~~

自豪的采用 HydroJudge 进行评测(github.com/hydro-dev/HydroJudge)

{"receive":"2020-07-21T15:51:03.560Z","handle":"2020-07-21T15:51:03.560Z","done":"2020-07-21T15:51:03.948Z"}