foo.cc:2:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){register long long a,b;scanf("%lld%lld",&a,&b);printf("%lld",a+b);}
      ^
foo.cc: In function 'int main()':
foo.cc:2:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 main(){register long long a,b;scanf("%lld%lld",&a,&b);printf("%lld",a+b);}
                               ~~~~~^~~~~~~~~~~~~~~~~~

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

{"receive":"2020-08-08T14:27:54.868Z","handle":"2020-08-08T14:27:54.868Z","done":"2020-08-08T14:27:55.234Z"}