/in/foo.cc: In function 'int main()':
/in/foo.cc:6:23: error: 'cin' was not declared in this scope
  while(a[i-1]||a[i-2])cin>>a[i],i++;
                       ^
/in/foo.cc:8:2: error: 'cout' was not declared in this scope
  cout<<a[j]+a[j+1]<<endl;
  ^
/in/foo.cc:8:21: error: 'endl' was not declared in this scope
  cout<<a[j]+a[j+1]<<endl;
                     ^