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;    }   };