合并两个顺序链表

使用递归

#include <iostream>
using namespace std;
typedef struct _Node
{
  int data;
  struct _Node *next;

}Node,*PNode;
PNode BuildList()
{
   
   int data;
   int i=0;
   PNode head,p,pfront;
   cin>>data;
   while(data!=-1)
   {
	   i++;
	   p=(PNode)malloc(sizeof(Node));
	   p->data=data;
	   p->next=NULL;
	   if(i==1)
		   head=p;
	   else
	   {
		   pfront->next=p;
       }
	   pfront=p;
	   cin>>data;
   }
   return head;

}
PNode MergeSortList(PNode p1,PNode p2)
{
  PNode ret;
  if(!p1)
	  return p2;
  if(!p2)
	  return p1;
  if(p1->data<p2->data)
  {
    ret=p1;
	p1->next=MergeSortList(p1->next,p2);
  }
  else
  {
    ret=p2;
	p2->next=MergeSortList(p1,p2->next);
  }
 return ret;
}
void Print(PNode p)
{
	PNode tmp=p;
	while(tmp)
	{
		cout<<tmp->data<<endl;
		tmp=tmp->next;
	}
}
int main()
{ 
 PNode head;
 PNode p1;
 PNode p2;
 p1=BuildList();
  Print(p1);
 p2=BuildList();
  Print(p2);
 head=MergeSortList(p1,p2);


 Print(head);

 
  return 0;
}