2,Add Two Number (LinkList Math)

/*
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
*/


#include<stdlib.h>
#include<stdio.h>

struct ListNode {
           int val;
           struct ListNode *next;
};

void printList(ListNode *& header){
           if (header == NULL){
                    return;
          }

           ListNode* node = header ;
           while (node != NULL ){
                   printf( "%d   ", node->val);
                   node = node->next;
          }
          printf( "\n");
}

void createList(ListNode *& header, int * array , int len){
           header = (ListNode *)malloc(sizeof( ListNode));
           ListNode* tailer = header ;

           ListNode* tempNode = NULL ;
           ListNode* pre = header ;
           for (int i = 0; i < len; i++){
                   tailer->val = *( array+i);
                   pre = tailer;
                   tempNode = ( ListNode*)malloc(sizeof (ListNode));
                   tailer->next = tempNode;
                   tailer = tempNode;
          }

          pre ->next= NULL;
}


 ListNode* addTwoNumbers( ListNode* l1 ,  ListNode* l2) {

           if (l1 == NULL){
                    return l2 ;
          }

           if (l2 == NULL){
                    return l1 ;
          }

           ListNode* header = (ListNode *)malloc(sizeof( ListNode));
           ListNode* tailer = header;

           ListNode* tempNode = NULL ;
           ListNode* pre = header;

           int isIncress = 0;
           while (l1 != NULL && l2 != NULL ){

                    int value = l1 ->val + l2->val;

                    if (isIncress){
                             value += 1;
                             isIncress = 0;
                   }
                    if (value >= 10)      {
                             value = value % 10;
                             isIncress = 1;
                   }

                   tailer->val = value;
                   pre = tailer;
                   tempNode = ( ListNode*)malloc(sizeof (ListNode));
                   tailer->next = tempNode;
                   tailer = tempNode;

                    l1 = l1 ->next;
                    l2 = l2 ->next;
          }

           if (l1 == NULL && l2 == NULL && isIncress){
                   tailer->val = 1;
                   pre = tailer;
                   tempNode = ( ListNode*)malloc(sizeof (ListNode));
                   tailer->next = tempNode;
                   tailer = tempNode;

                   isIncress = 0;
          }

           while (l1 != NULL){
                    int value = l1 ->val;

                    if (isIncress){
                             value += 1;
                             isIncress = 0;
                   }
                    if (value >= 10)      {
                             value = value % 10;
                             isIncress = 1;
                   }

                   tailer->val = value;
                   pre = tailer;
                   tempNode = ( ListNode*)malloc(sizeof (ListNode));
                   tailer->next = tempNode;
                   tailer = tempNode;

                    l1 = l1 ->next;
          }

           while (l2 != NULL){
                    int value = l2 ->val;

                    if (isIncress){
                             value += 1;
                             isIncress = 0;
                   }
                    if (value >= 10)      {
                             value = value % 10;
                             isIncress = 1;
                   }

                   tailer->val = value;
                   pre = tailer;
                   tempNode = ( ListNode*)malloc(sizeof (ListNode));
                   tailer->next = tempNode;
                   tailer = tempNode;

                    l2 = l2 ->next;
          }

           if (isIncress){
                   tailer->val = 1;
                   pre = tailer;
                   tempNode = ( ListNode*)malloc(sizeof (ListNode));
                   tailer->next = tempNode;
                   tailer = tempNode;
          }

          pre ->next= NULL;

           return header;
}


int main(){

           int array1[1] = { 1 };

           int array2[2] = {  9,9 };

           ListNode * h1 = NULL ;
           ListNode * h2 = NULL ;


          createList(h1, array1, 1);
          createList(h2, array2, 2);

          printList(h1);
          printList(h2);
           ListNode* result = addTwoNumbers(h1, h2);
          printList(result);

          printf( "Hello world \n");
           return 0;
}