text: Create third doubly linked List List3 . 8 <= > 11 <= > 13 <= > 18
code: head [ 2 ] = append ( head [ 2 ] , 8 ) ; head [ 2 ] = append ( head [ 2 ] , 11 ) ; head [ 2 ] = append ( head [ 2 ] , 13 ) ; head [ 2 ] = append ( head [ 2 ] , 18 ) ;