LeeCode---Add Two Numbers

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
int In=0;
ListNode *pHead=new ListNode(0);
ListNode *p=pHead;

while(l1!=NULL||l2!=NULL)
{
int temp1=0;
if(l1!=NULL)
{
temp1=l1->val;
l1=l1->next;
}

int temp2=0;
if(l2!=NULL)
{
temp2=l2->val;
l2=l2->next;
}

int temp=temp1+temp2+In;
p->next=new ListNode(temp%10);
In=temp/10;

p=p->next;
}

if(In==1)
p->next=new ListNode(1);

return pHead->next;
}
};