insert Nodes in the circular linked list
struct Node * head = NULL ; insertNode ( & head , 1 ) ; insertNode ( & head , 2 ) ; insertNode ( & head , 3 ) ; insertNode ( & head , 4 ) ; insertNode ( & head , 5 ) ; insertNode ( & head , 6 ) ; insertNode ( & head , 7 ) ; insertNode ( & head , 8 ) ; insertNode ( & head , 9 ) ; int k = 4 ;