Add Two Numbers

You are given two non-empty linked lists representing two non-negative integers. 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.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {
     int x,y,temp = 0;
     int result;
     struct ListNode *head  = (struct ListNode*)malloc(sizeof(struct ListNode));
     struct ListNode *ptr   = head;
     struct ListNode *ptr1  = head;
    while(l1!= null || l2!= null)
    {
       x = (l1 != null)?l1->val:0;
       y = (l2 != null)?l2->val:0;
       result = (temp+x+y)%10;
       temp   = (temp+x+y)/10;
       ptr = (struct ListNode*)malloc(sizeof(struct ListNode));
       ptr->val   = result;
       ptr->next  = null  ;
       ptr1->next = ptr;
       ptr1 = ptr;
       l1 = (l1!= null)?l1->next:null;
       l2 = (l2!= null)?l2->next:null;
    }
    
    if(temp > 0)
    {
        ptr = (struct ListNode *)malloc(sizeof(struct ListNode));
        ptr->val = temp;
        ptr->next = null;
        ptr1 ->next = ptr;
    }
    return head->next;
}

 

在第一次进行编译的时候，错误提示：

member access within misaligned address 0x000000000031 for type 'struct ListNode', which requires 8 byte alignment，

在申请空间时代码如下：

ptr = (struct ListNode*)malloc(sizeof(struct ListNode));

由于结构体内存在next指针，而申请结构体空间后同时定义了next指针，此时next指针未指向任何空间，故在测试时可能导致上述错误。

解决方法为：

增加代码使next指针指向空。

ptr->next=NULL;