18. Declare the following node for a binary search tree: struct node { node *left; int data; node *right; where left is a pointer to the left subtree and right is a pointer to the right subtree. Write a C program that inputs a sequence of integers with -9999 as a sentinel and inserts them into a binary search tree. Output them in ascending order with a recursive procedure that makes an inorder traversal of the search tree. Sample Input 40 90 50 10 80 30 70 60 20 -9999 Sample Output 10 20 30 40 50 60 70 80 90