删除链表中重复的节点

#include <iostream>
#include <algorithm>
using namespace std;


class ListNode{
public:
  int val;
  ListNode *next;
};

void create(ListNode *L)
{
    ListNode* p = new ListNode;
    int data;
    cin>>data;
    p->val = data;
    while(data!=0)
    {
        p->next = NULL;
        L->next = p; 
        L = L->next;
        p = new ListNode;
        cin>>data;
        p->val = data;
    }
}


ListNode* delWholDulRecur(ListNode *pHead)
{
   if(pHead==NULL||pHead->next==NULL)
        return pHead;
    if(pHead->val==pHead->next->val)
    {
        ListNode* pNode = pHead->next;
        while(pNode!=NULL&&pNode->val==pHead->val)
        {
            pNode = pNode->next;
        }
        return delWholDulRecur(pNode);
    }
    else
    {
        pHead->next = delWholDulRecur(pHead->next);
    }
    return pHead;
}

void delWholDul(ListNode *L)
{
    ListNode *pre = L,*p = L->next,*q,*r;
    while(p!=NULL&&p->next!=NULL)
    {
        if(p->val==p->next->val)
        {
            while(p->val==p->next->val&&p!=NULL&&p->next!=NULL)
            {
                r = p;
                q = p->next;
                p->next = q->next;
                delete q;
            }
            pre->next = p->next;
            delete r;
            p = pre->next;
        }
        else
        {
            p = p->next;
            pre = pre->next;
        }
    }
}

void delNode(ListNode *L)//去重代码
{
    ListNode *p = L->next,*q;
    while(p!=NULL&&p->next!=NULL)
    {
        if(p->val==p->next->val)
        {
            q = p->next;
            p->next=q->next;
            free(q);
        }
        else
        {
            p=p->next;
        }
    }
}

void show(ListNode *L)
{
    ListNode *p = L->next;
    while(p)
    {
        cout<<p->val<<" ";
        p=p->next;
    }
    cout<<endl;
}
int main()
{
    ListNode *L1 = new ListNode;
    ListNode *L2 = NULL;
    L1->next = NULL;
    create(L1);
   // delNode(L1);
   //delWholDul(L1);
   L2 = delWholDulRecur(L1);
    show(L2);
    return 0;
}