两个线性表怎么合并为一个线性表

求问，这个代码要怎么写

#include <stdio.h>
#include <stdlib.h>
#define MAX1 10
#define MAX2 6
typedef struct list
{
   int num;
   struct list *next;
}*link;

int data1[MAX1] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int data2[MAX2] = { 11, 12, 13, 14, 15, 16 };

link create_list(link head, int *data, int MAX)
{
   link newnode;
   link pointer;
   int i;

   head = malloc(sizeof(*head));
   if(head==NULL)
      printf("Memory allocate Failure!\n");
   else
   {
      head->num = data[0];
      head->next = NULL;

      pointer = head;

      for(i=1; i<MAX; ++i)
      {
         newnode = malloc(sizeof(*newnode));
         if(newnode==NULL) break;
         newnode->num = data[i];
         newnode->next = NULL;

         pointer->next = newnode;
         pointer = newnode;
      }
   }
   return head;
}

void free_list(link head)
{
   link pointer;

   while(head!=NULL)
   {
      pointer = head;
      head = head->next;
      free(pointer);
   }
}

void print_list(link head)
{
   if(head==NULL)
      printf("empty!");
   while(head!=NULL)
   {
      printf("[%d]", head->num);
      head = head->next;
   }
   putchar('\n');
}

link concat(link head1, link head2)
{
   link pointer = head1;

   if(head1!=NULL && head2!=NULL)
   {
      while(pointer->next!=NULL)
         pointer = pointer->next;
      pointer->next = head2;
   }
   else if(head1==NULL && head2!=NULL)
      head1 = head2;
   return head1;
}

int main(void)
{
   link head  = NULL;
   link head1 = NULL;
   link head2 = NULL;   

   head1 = create_list(head1, data1, MAX1);
   head2 = create_list(head2, data2, MAX2);
 
   if(head1!=NULL && head2!=NULL)
   {
      printf("Input data :\n");
      print_list(head1);
      print_list(head2);

      head = concat(head1, head2);
      //head = concat(NULL, head2); 
      //head = concat(head1, NULL);
      //head = concat(NULL, NULL); free(head1); free(head2);
      printf("After concat:\n");
      print_list(head);
      free(head1);
   }

   return 0;
}