想了很久还是不知道怎么改程序

#include "iostream.h"
#include "stdlib.h"
#include "math.h"
#define ElemType int
#define OK 1
#define ERROR 0
#define N 6
typedef struct LNode
{
ElemType data;
struct LNode *next;
int length;
}LNode,*LinkList;
LNode *creat_L();
void out_L(LNode *L);
void insert_L(LNode *L,int i ,ElemType e);
ElemType delete_L(LNode *L,int i);
int locat_L(LNode *L,ElemType e);

int InitList_Sq(LinkList &L)
{
L=(LNode*)malloc(sizeof(LNode));
L->next=NULL;
return OK;
}//初始化
int ListInsert_L(LinkList &L,int i,ElemType &e)

{
LNode *s,*p;int j;
p=L,j=0;
while(p&&j<i-1){p=p->next;++j;}
if(!p||j>i-1)return ERROR;
s=(LinkList)malloc(sizeof(LNode));
s->data=e;s->next=p->next;
p->next=s;
return OK;
}//输入
int ListDelete_L(LinkList &L,int i,ElemType &e)
{
LNode *p,*q; int j;
p=L,j=0;
while(p->next&&j<i-1){p=p->next;++j;}
if(!(p->next)||j>i-1) return ERROR;
q=p->next;p->next=q->next;
e=q->data;free(q);
return OK;
}//删除
int GetElem_L(LinkList L,int i,ElemType &e)
{
LNode *p; int j;

p=L->next;
j=1;
while(p&&j<i){p=p->next;++j;}
if(!p||j>i) return ERROR;
e=p->data;
return OK;
}//取表中第i个元素
int length_L(LinkList &L ,int i)
{ LinkList p;
i=0;
p=L->next;
while(p)
{i++;p=p->next;}
return i;
}//求表长
int ListElem_L(LinkList L,ElemType e)
{ int i;
i=L[0].data;
while(i&&L[i].data!=e)i=L[i].data;
return i;
}
void print_L(LinkList L)
{
LNode *p;
p=L->next;
cout<<endl;
while(p!=NULL)
{
cout<<p->data;
p=p->next;
}
} //显示
void main()
{
int i; ElemType e;
LinkList L;
InitList_Sq(L);


cout<<"1.建立单链表L"<<endl;
cout<<"2.插入元素e"<<endl;
cout<<"3.删除表中第i个元素"<<endl;
cout<<"4.取表中第i个元素"<<endl;
cout<<"5.退出"<<endl;
cout<<"按数字键选择: "<<endl;
int s;
cin>>s;
while(s!=4)
{
switch(s)
{
case 1:
cout<<"输入几个元素组成单链表L"<<endl;
for(i=1;i<=N;i++)
{
cin>>e;ListInsert_L(L,i,e);
}
print_L(L);
cout<<endl;
//break;
case 2:
cout<<"向表中插入元素: "<<endl;
cin>>s;
cout<<endl;
ListInsert_L(L,i,s);
cout<<"插入后的单链表为: "<<endl;
print_L(L);
cout<<endl; //break;
case 3:
cout<<"输入要删除的元素:"<<endl;
int s;
cin>>s;
i=0;
while(i<N)
{
if(L->data==s)
{
ListDelete_L(L,i+1,e);
cout<<"删除的元素存在 :e="<<e<<endl;break;
}
i++;
}
if(i>=N) cout<<"要删除的元素不存在";
else
{
cout<<"删除后的单链表为: "<<endl;
print_L(L);
}
cout<<endl;return;
//break;
case 4:
cout<<"从表中查找元素: <<"<<endl;
cin>>s;
cout<<endl;
ListElem_L(L,e);
cout<<"插入后的单链表为: "<<endl;
print_L(L);
cout<<endl;return;
break;
case 5:return;
default:
cout<<"按任意键退出!"<<endl;


}

}



}

编译结果是：
j:\数据结构\单链表\单链表.cpp(146) : warning C4700: local variable 'e' used without having been initialized

单链表.obj - 0 error(s), 0 warning(s)