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Sum Them All Linked List

Write a function that traverses a singly$-$linked list finding the ALL sum of all the integers in each node. Each node instance, a LinkedListNode, has an integer, data, and a pointer to the next node, next. Given a reference to the head of a singly$-$

$($i$)$ linked list, find the sum.

$1$ Function Description

Complete the function linkedListSum in the editor below.

$2$

linkedListSum has the following parameter$($s$)$:

head: reference to the head of a singly$-$linked list of integers

$3$

Returns:

$4$

int: an integer of the sum

Constraints

$5$

$-1**{10}^4$ LinkedListNode.data ${10}^4$

$0$ LinkedList size $<mn>1</mn><mn>0</mn><mn>0</mn>$

Input Format for Custom Testing

Sample Case $0$

Sample Input$546-7423$Sample OutputTest ResultsCustom InputLine: $$Run CodeRun Tests