推免复习-数据结构-链栈

#include<iostream>//链栈，不用设头结点 
using namespace std;
struct node
{
	int data;
	node *next;
};
class Linkstack
{
	private:
		node *top;//栈顶指针 
	public:
		Linkstack(){
			top=NULL;
		}
		~Linkstack()
		{
			while(empty()==false)
			{
				pop();
			}
			delete top;
		}
		void push(int x)
		{
			node *s=new node;
 			s->data=x;
 			s->next=top;
 			top=s;
		}
		int pop()
		{
			if(top==NULL)
			throw"下溢"; 
			int x=top->data;
			node *p=top;
			top=top->next;
			delete p;
			return x;
		}
		int gettop()
		{
			int x=top->data;
			return x;
		}
		bool empty()
		{
			if(top==NULL)
			return true;
			else return false;
		}
 };
 int main()
 {
 	Linkstack ls;
 	ls.push(7897);
 	cout<<"top:"<<ls.gettop()<<endl;
 	ls.pop();
 	cout<<"empty():"<<ls.empty()<<endl;	
 }