/in/foo.cc: In function 'int main()':
/in/foo.cc:7:8: error: 'cin' was not declared in this scope
  while(cin>>a){
        ^
/in/foo.cc:9:2: error: 'cout' was not declared in this scope
  cout<<a+b<<endl;
  ^
/in/foo.cc:9:13: error: 'endl' was not declared in this scope
  cout<<a+b<<endl;
             ^