foo.cc: In function 'int main()':
foo.cc:9:2: error: 'cout' was not declared in this scope
  cout<<Findmax(a,n)<<endl;
  ^~~~
foo.cc:9:22: error: 'endl' was not declared in this scope
  cout<<Findmax(a,n)<<endl;
                      ^~~~
foo.cc:9:22: note: suggested alternative: 'enum'
  cout<<Findmax(a,n)<<endl;
                      ^~~~
                      enum
foo.cc: In function 'int Input(int*)':
foo.cc:25:9: error: 'cin' was not declared in this scope
  int n; cin>>n;
         ^~~
foo.cc:25:9: note: suggested alternative: 'main'
  int n; cin>>n;
         ^~~
         main
foo.cc: In function 'int Findmax(int*, int)':
foo.cc:22:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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