/in/foo.cc: In function 'int main()':
/in/foo.cc:8:2: error: 'cin' was not declared in this scope
  cin>>xmax;
  ^~~
/in/foo.cc:30:2: error: 'cout' was not declared in this scope
  cout<<cnt<<endl;
  ^~~~
/in/foo.cc:30:13: error: 'endl' was not declared in this scope
  cout<<cnt<<endl;
             ^~~~