[Click] using ifstream in .cc element file

[Bhurat Prateek]

  CXX ../elements/ethernet/abilene.cc
../elements/ethernet/abilene.cc: In member function ‘virtual Packet* Abilene::simple_action(Packet*)’:
../elements/ethernet/abilene.cc:50: error: ‘ifstream’ was not declared in this scope
../elements/ethernet/abilene.cc:50: error: expected `;' before ‘fin’
../elements/ethernet/abilene.cc:51: error: ‘fin’ was not declared in this scope
../elements/ethernet/abilene.cc:59: error: ‘fp’ was not declared in this scope
../elements/ethernet/abilene.cc:63: error: ‘q’ was not declared in this scope

How can I read and write to a text file from a  .cc element file.I tried using ifstream after including the fstream header file.But it doesn't seem to work.