Is the output really 6->6->6->6->, or is it ->6->->6->->6->->6-> ? Make sure you state EXACTLY the output from the program (for example, you've changed "poped" to "popped", so clearly either you haven't given the output from the program or you've changed the code since posting it).

cout << "->" <<data << "->",temp->data;

Interesting use of the comma operator. Maybe have another look at this line?

Edit: oh yeah, and you've got a memory leak in case 2.