foo.c: In function 'main':
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%f %f %f %f", &a, &b, &c, &d);
  ^

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

{"receive":"2020-03-29T23:28:02.311Z","handle":"2020-03-29T23:28:02.311Z","cache_start":"2020-03-29T23:28:02.327Z","read_cases":"2020-03-29T23:28:02.426Z","judge":"2020-03-29T23:28:02.426Z","done":"2020-03-29T23:28:02.513Z"}