create linked list 10 -> 12 -> 8 -> 4 -> 6
head = push ( head , 6 ) ; head = push ( head , 4 ) ; head = push ( head , 8 ) ; head = push ( head , 12 ) ; head = push ( head , 10 ) ; Console . WriteLine ( " Linked ▁ list ▁ before ▁ sorting : " ) ; printList ( head ) ;