未声明的标识符错误

#include<iostream>
using namespace std;
struct element
{
    int val;
    element *next;
};
class list
{
element *elems;
public:
    list(){elems=0;}
    ~list();
    virtual bool insert(int val);
    virtual bool deletes(int val);
    bool contain(int val);
    virtual void print();
};
class set:public list
{
    int card;
public:
    set(){card=0;};
    bool insert(int val);
    bool deletes(int val);
    void print();
};
list::~list()
{
    element *tmp=elems;
    for(element *elem=elems;elem!=NULL;)
    {
        tmp=elem;
        elem=elem->next;
        delete tmp;
    }
}
bool list::insert(int val)
{
    elememt* elem=new element;
    if(elem!=NULL)
    {
        elem->val=val;
        elem->next=elems;
        elems=elem;
        return true;
    }
    else return false;
}
bool list::deletes(int val)
{
    if(elems==NULL)
        return false;
    element *tmp=elems;
    if(elems->val==val)
    {
        elems=elems->next;
        delete tmp;
        return true;
    }
    else
        for(element *elem=elems;elem!=NULL;elem=elem->next)
            if(elem->next->val==val)
            {
                tmp=elem->next;
                elem->next=tmp->next;
                delete tmp;
                return true;
            }
            return false;
}
bool list::contain(int val)
{
    if(elems==NULL)
        return false;
    if(elems->val==val)
        return true;
    else
        for(element *elem=elems;elem!=NULL;elem=elem->next)
            if(elem->next->val==val)
                return true;
    return false;
}
void list::print()
{
    cout<<"调用基类的print()函数！"<<endl;
    cout<<"链表元素为：";
    if(elems==NULL)
        return;
    for(element *elem=elems;elem!=NULL;elem=elem->next)
        cout<<elem->val<<"  ";
    cout<<endl;

}
bool set::insert(int val)
{
    if(!contain(val) && list::insert(val))
    {
        ++card;
        return true;
    }
    return false;
}
bool set::deletes(int val)
{
    if(list::deletes(val)){
        --card;
        return true;}
    return false;
}
void set::print()
{
    cout<<"调用派生类的print()函数！"<<endl;
    cout<<"集合元素为：";
    list::print();
    cout<<"集合元素个数为："<<card;
    cout<<endl;
}
int main()
{
    list *p,list1;
    set set1;
    p=&list1;
    p->insert(12);
    p->insert(34);
    p->insert(56);
    p->insert(78);
    p->insert(90);
    p->print();
    p->deletes(56);
    p->deletes(40);
    p->print();
    cout<<endl;
    p=&set1;
    p->insert(123);
    p->insert(234);
    p->insert(345);
    p->insert(123);
    p->print();
    p->deletes(123);
    p->deletes(456);
    p->print();
    return 0;
}


sdf.cpp
d:\文件\头文件\sdf\sdf\sdf.cpp(40) : error C2065: “elememt”: 未声明的标识符
d:\文件\头文件\sdf\sdf\sdf.cpp(40) : error C2065: “elem”: 未声明的标识符
d:\文件\头文件\sdf\sdf\sdf.cpp(41) : error C2065: “elem”: 未声明的标识符
d:\文件\头文件\sdf\sdf\sdf.cpp(43) : error C2065: “elem”: 未声明的标识符
d:\文件\头文件\sdf\sdf\sdf.cpp(43) : error C2227: “->val”的左边必须指向类/结构/联合/泛型类型
        类型是“'unknown-type'”
d:\文件\头文件\sdf\sdf\sdf.cpp(44) : error C2065: “elem”: 未声明的标识符
d:\文件\头文件\sdf\sdf\sdf.cpp(44) : error C2227: “->next”的左边必须指向类/结构/联合/泛型类型
        类型是“'unknown-type'”
d:\文件\头文件\sdf\sdf\sdf.cpp(45) : error C2065: “elem”: 未声明的标识符
生成日志保存在“file://d:\文件\头文件\sdf\sdf\Debug\BuildLog.htm”
sdf - 8 个错误，0 个警告