public void actionPerformed(ActionEvent e)
		{
			if (e.getActionCommand().equals("postOrder")){
				tree.postOrder();	
			}
			else if (e.getActionCommand().equals("insert")){
				tree.insertFromInput();
			}
			else if (e.getActionCommand().equals("clear")){
				tree.clear();
			}
			else if (e.getActionCommand().equals("delete")){
				tree.deleteFromInput();
			}
			else if (e.getActionCommand().equals("inOrder")){
				tree.inOrder();
			}
			else if (e.getActionCommand().equals("preOrder")){
				tree.preOrder();
			}
			else if (e.getActionCommand().equals("HELP")){
				JOptionPane.showMessageDialog(null, "Select a DEPARTURE and DESTINATION city and press FIND FLIGHT" ,"Help",JOptionPane.PLAIN_MESSAGE); 
			}
			else if (e.getActionCommand().equals("EXIT")){
				System.exit(0);
			}		
		}