Add Two Numbers

/**
* 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) {
ListNode*res=new ListNode(0);
ListNode*re=res;
int carry=0;
int flag=0;
while(l1!=NULL||l2!=NULL){
int v1,v2;
v1=(l1==NULL?0:l1->val);
v2=(l2==NULL?0:l2->val);
int temp=v1+v2+carry;
res->next=new ListNode(temp%10);
carry=temp/10;
if(l1!=NULL)
l1=l1->next;
if(l2!=NULL)
l2=l2->next;
res=res->next;
}
if(carry>0)
res->next=new ListNode(carry);
return re->next;
}
};