遇到 unexpected type 不懂什么意思，求教！！

写一个一个链表的程序：

LinearList.h 如下

#include<iostream>

class ListNode
{
public:
int key;
ListNode *next;
ListNode():next(NULL){}
ListNode(int x):key(x),next(NULL){}
~ListNode();

};

class LinearList
{

private:
int size;
ListNode *head;

public:
LinearList(void) ;
~LinearList(void);
bool insert(int x, int pos);
bool remove(int &x, int pos);
int element(int pos) const;
int search(int x) const;
int length() const;
(ListNode*) find(int i)const;
};

LinearList.cpp 如下

#include"LinearList.h"


LinearList::LinearList(void)
{
size = 0;
head = new ListNode();
head->next = NULL;
}

(ListNode*) LinearList::find(int i) //此处有错，见下面的error
{
ListNode *node = head;
int x = 0;
while ((x++<i)&&(node!=NULL))
node = node->next;
return node;
}

bool LinearList::insert(int x, int pos)
{
if(x<0 || x>size)
{
std::cout<<"ArrayOutOfBound!";
return false;
}

ListNode *node = new ListNode(x);
ListNode *cur = find(pos);
node->next = cur->next;
cur->next = node;
size++;
return true;
}

bool LinearList::remove(int &x, int pos)
{
if(x<=0 || x>size)
{
std::cout<<"ArrayOutOfBound!";
return false;
}

ListNode *pre = find(pos-1);
ListNode *del = pre->next;
x = del->key;
pre->next = del->next;
delete del;
size--;
return true;

}

int LinearList::element(int pos) const
{
if(pos<=0 || pos>size)
{
std::cout<<"ArrayOutOfBound!";
return 0;
}

ListNode *cur;
cur = find(pos);
return cur->key;
}

//查找值为x的元素，返回元素的位置（第一个元素的位置为1）。未找到时返回0。
int LinearList::search(int x) const
{
int i = 1;
ListNode *itr = head->next;
while(itr!=NULL && itr->key!=x)
{
itr = itr->next;
i++;
}
return i;
}

inline int LinearList::length() const
{
return size;
}



编译报错：
error C2226: syntax error : unexpected type 'ListNode'
error C2143: syntax error : missing ';' before '{'
error C2447: '{' : missing function header (old-style formal list?)

小弟学习c++不久，望高手不吝赐教~~~~