链表的创建等一系列操作

#include <stdio.h >
#include <iostream>

using namespace std;

typedef int DataType; 
typedef struct Node
{
DataType data;
struct Node * next;
}Node,*LinkList;

void CreateListH(LinkList &L)//头插法 
{
cout<<"请输入数\n";
Node *s;
int c;
L = new Node;
L->next = NULL;
    cin>>c;
    while (c != 0)
    {
    s = new Node;
    s->data = c;
    s-> next = L->next;
    L->next = s;
        cin>>c;

}
}
void CreateListT(LinkList &L)//尾插法 
{
int c;
cout<<"please input\n";
Node *r,*s;
L = new Node;
L->next = NULL;
r = L;
cin >> c;
while(c != 0)
{
s = new Node;
s->data = c;
r->next = s;
r = s;
cin >> c;
}
r->next = NULL;
}



void Output(LinkList L)// l 头结点 
{
Node *p;
for(p=L->next;p != NULL;p=p->next)
printf("%d  ",p->data);
printf("\n");
}

Node * GetData(LinkList L,int i) //第i个节点的位置 
{
int j;
Node *p;
cout << "input第几个节点\n";
cin >> i;
i = i-1;
if (i < 0)
  return NULL;
p = L;//p  point to head
j = 0;//count++
while (p->next != NULL && j < i)
{
p = p->next;
j++;
}
if (i == j) 
return p;
else 
return NULL;
}


int Length(LinkList L)//计算长度 
{
Node *p;
int len = 0;
p  = L->next;
while(p != NULL)
{
p= p->next;
len++;
}
 return len;
}



void Delete(LinkList &L,int i)//删除 
{
Node *pre,*r;
cout << "please input which node will be deleted\n";
pre = GetData(L,i-1);
if (pre == NULL ||  pre->next == NULL)
printf("delete is unreasonable\n");
else 
{
r = pre->next;
pre->next = r->next;
delete(r);
}
}


void Insert(LinkList &L,int i,DataType x)//在第i个节点前插入x的新节点
{
Node *pre,*s;
cout << "input x (待插入)\n";
cin >> x;
pre = GetData(L,i-1);
if (pre == NULL)
printf("error\n");
else 
{
s = new Node;
s->data = x;
s->next = pre->next;
pre->next = s;
}


 } 


int main()
{
Node *L;
int c,d,x,i;
cout<<"choose  way\n";// 头插还是尾插 
cin >> c;
if (c == 1)
    CreateListH(L);

else
CreateListT(L);
d = Length(L);
cout << d << endl;
Insert(L, i,x);
Output(L);
Delete(L, i);
Output(L);

}