Header file is given. Implement those functions above in C. And a validation function defined below. Thank You.

#ifndef LIST H 2 #define LIST H 4 #include 5 #include 7 struct ListNode f long value; struct ListNode *prev; struct ListNode xnext; 10 12 13 struct ListNode list_prepend(struct ListNode list, long value); 14 struct ListNode list_append (struct ListNode list, long value); 15 struct ListNode list_remove(struct ListNode list, struct ListNode *node); 16 struct ListNode list_remove_value(struct ListNode list, long value); 17 struct ListNode xlist_find(struct ListNode list, long value); 18 struct ListNode list_insert (struct ListNode list, struct ListNode after, 19 20 int list_count(struct ListNode list, long value); 21 22 bool list_validate(struct ListNode list); 23 24 #endif/* LISTH*/ struct ListNode xnode); - - bool list validate(struct ListNode *list): This returns true if list is the head of a list that meets the structural requirements of a well-formed list, and false for any other list. It should not crash for a badly-formed list when the invalid structure can be detected, but may crash if the list is badly formed in a way that cannot be detected (e.g., containing an invalid pointer that is not NULL)