Write a function named removeBack that accepts a reference to a pointer to a ListNode representing the front of a linked list.
Your function should remove the node at the end of the list.
For example, suppose a variable named front points to the front of a list containing the following sequence of values:
{8, 23, 19, 7, 102}
The call of removeBack(front); should change the list to store the following:
{8, 23, 19, 7}
The other values in the list should retain the same order as in the original list.
Your function should not leak memory; if your function removes a node, you should free (delete) the memory used by the node.
If the list is already empty (null), your function should have no effect.
Constraints:
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 modify the data field of existing nodes; change the list by changing pointers only.
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)
}
