请大家帮个忙,关于c++中结构指针的问题

[zcl198715]

//本程序是为了建一个链表!
//并完成相关操作
#include<iostream>
#include<string>
using namespace std;
struct student
{
	string name;
	student *next;
};
void creat(student *first)//建立链表,并输入数据
{
	student *current;
	int a;
	first=current=new student;
	cout<<"输入姓名:\n";
	cin>>current->name;
	cout<<"继续输入(yes==1,no==0)"<<'\n';
	cin>>a;
	while(a)
	{
		current=current->next=new student;
		cin>>current->name;
		cout<<"继续输入(yes==1,no==0)"<<'\n';
	    cin>>a;
	}
	current->next=0;
	cout<<"输入完成!\n";
}
void print(student *first)//输出
{
	student *current;
	current=first;
	while(current!=0)
	{
		cout<<current->name<<'\n';
		current=current->next;
	}
}
void destroy(student *first)//销毁
{
	student *current;
	while(first!=0) 
	{
		current=first->next;
		delete first;
		first=current;
	}
	cout<<"删除成功\n";

}
int main()
{
	student *first=NULL;//为什么要将first赋值为NULL,可不可以不赋值啊?
	creat(first);
	print(first);//通过测试,我发现first为空,为什么?也就是说,first=0
	destroy(first);
	return 0;
}

希望大家能给些帮助,不胜感谢!

[lsldd]

void creat(student* &first)//注意，加上&，表示传引用！才能在函数里面改变first指针的值！

student *first=NULL;//指针一定要初始化！否则是野指针！没有初始化，无法预料他指向哪里！