loop to perform operations to remove key to end
while ( current != tail ) { if ( current . data == key && prev2 == null ) { prev = current ; current = current . next ; head = current ; last . next = prev ; last = last . next ; last . next = null ; prev = null ; } else { if ( current . data == key && prev2 != null ) { prev = current ; current = current . next ; prev2 . next = current ; last . next = prev ; last = last . next ; last . next = null ; } else if ( current != tail ) { prev2 = current ; current = current . next ; } } } return head ; }