怎样用C++实现基本的链表类？？？？？

// c++
#include <iostream.h>
struct ListNode{
char data;
ListNode * nextPtr;
};
class List
{
public:
List();
void insertList(char);
char deleteList(char);
int isempty();
void printList();

private:
ListNode * head;
};

List::List(){
head = NULL;
}

void List::insertList(char item){
ListNode * previousPtr, * currentPtr, * newPtr;
newPtr = new ListNode;

if(newPtr != NULL){ //链表建立成功
newPtr -> data = item;
newPtr -> nextPtr = NULL;
previousPtr = NULL;
currentPtr = head;
while(currentPtr != NULL){
previousPtr = currentPtr;
currentPtr = currentPtr -> nextPtr;
}
if(previousPtr == NULL){ //链表为空
newPtr -> nextPtr = NULL;
head = newPtr;
}
else{
previousPtr -> nextPtr = newPtr;
newPtr ->nextPtr = NULL;