请问下：怎么把类ActList中的Create函数拿到类外面来定义，我试了下老报错

#include "stdafx.h"
#include <iostream>
using namespace std;
class ActList;
class ListNode
{
 friend class ActList;
public:
    char ActName[20];
    char director[20];
    int Mtime;
    ListNode *next;
 ListNode(){};
 ~ListNode(){};
};
class ActList
{
public:
 ListNode *head; 
 void displayList(ListNode *pHead);
    ActList(){};
 ~ActList(){};
 ListNode *Create()
 {
  ListNode *p = NULL;            //待插入的节点
  ListNode *q = NULL;            //当前节点，用于在其后插入节点
        head = NULL;
  int Time;
  cout<<"输入节目时长:";
  cin>>Time;
  while (Time != 0)
  {
   p = new ListNode;
   p->Mtime = Time;
   cout<<"输入节目名称:";
   cin>>p->ActName;
   cout<<"输入主持人:";
   cin>>p->director;
   if (head == NULL)
   {
    head = p;
   }
   else
   {
    q->next = p;
   }
   q = p;
   cout<<"\n输入节目时长:";
   cin>>Time;
  }
  if (head != NULL)
  {
   q->next = NULL;
  }
  return(head);
 }
 
};

void ActList::displayList(ListNode *pHead)
{
 cout<<"\n显示节目列表\n";
 while(pHead != NULL)
 {
  cout<<pHead->Mtime<<endl
   <<pHead->ActName<<endl
   <<pHead->director<<endl
   <<endl;
  pHead = pHead->next;
 }
}

int main()
{
 ActList list;
    list.displayList(list.Create());
 return 0;
}