foo.cc: In function 'int main()':
foo.cc:8:6: warning: 'x' is used uninitialized in this function [-Wuninitialized]
  if(x%100==0)
     ~^~~~
foo.cc:33:8: warning: 'x1' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<x1<<endl;
        ^~
foo.cc:23:3: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(a==i)
   ^~

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