#include<iostream.h>
typedef int elemtype;
class node
{
public:
    elemtype data;
    node *next;
    void initset(node *head)
    {
        head=NULL;
    }
    void insert(node *head,elemtype i)  //插入   
    {
        node *p=new node;
        if(p!=NULL)
        {
            p->data=i;p->next=head;head=p;
        }
    }   
    void dele(node *head,elemtype i)        //删除
    {
        node *p=head,*q=NULL;
        while(p)
        {
            if(p->data=i)break;
            else
            q=p;p=p->next;
        }
        q->next=p->next;
        delete p;
    }
    bool find(node *head,elemtype i)         //查找
    {
        node *p=head;
        while(p)
        {
            if(p->data=i)
                return true;
            else
            p=p->next;
        }
    }
    void node::uion(node *head1,node *head2)       //交集放在head3里
    {
        node *head3;
        elemtype i;
        node *p=head2;
        while(p)
        {
            i=p->data;
            if(find(head1,i))
            insert(head3,i);
            p=p->next;
        }
    }

};

    void main()
    {
        node *head=NULL;
        node *Head1;
        node *Head2;
        node *Head3;
        node *p=head;
        int x;
        cout<<"输入链表："<<endl;
        cin>>x;
        while(x!=-1)
        {
            insert(Head2,x);
            cin>>x;
        }
        while(x!=-1)
        {
            insert(Head2,x);
            cin>>x;
        }

         Head3->uion(Head1,Head2);
         while(p)
         {
             cout<<p->data<<" ";
             p=p->next;
         }
    }
    
    
    
    
    //运行之后显示C:\Documents and Settings\Administrator\桌面\tt.cpp(71) : error C2065: 'insert' : undeclared identifier


这是关于一个求交集的问题