Write a function named reverse that accepts as a parameter a reference to a pointer to a ListNode representing the front of a linked list.
Your function should reverse the order of the elements in the list.
For example, if a variable named front points to the front of a list containing {1, 8, 19, 4, 17}, then after a call of reverse(front);, it should store {17, 4, 19, 8, 1}.
Constraints:
Do not modify the data field of existing nodes; change the list by changing pointers only.
Do not construct any new ListNode objects in solving this problem (though you may create as many ListNode* pointer variables as you like).
Do not use any auxiliary data structures to solve this problem (no array, vector, stack, queue, string, etc).
Assume that you are using the ListNode structure as defined below:
struct ListNode {
int data; // value stored in each node
ListNode* next; // pointer to next node in list (nullptr if none)
}
