（C++）数据结构学习一---栈

1.栈的概述

栈的主要特点是后进先出（last in first out,LIFO）,即出栈元素只能是位于栈顶的元素，入栈也只能在栈顶。

栈是只能在一端（栈顶）进行插入或删除的线性表。

n个元素依次入栈，可在任意时刻出栈，则共有

种可能。 

栈的存储结构：

                     

2.顺序栈代码实现

#ifndef _SEQSTACK_H
#define _SEQSTACK_H
#include<iostream>
using namespace std;
template<class T>
class SeqStack
{
public:
	SeqStack(int msize=10):top(-1),size(msize)
	{
		ptr=new T[size];
		if (ptr==NULL)
		{
			cout<<"创建失败！"<<endl;
			exit(1);
		}
	}
	~SeqStack()
	{
		delete [] ptr;
	}
	
	void push(const T item);
	T    pop();
	void print() const;
	T    getTop() const;
	
	bool isFull() const
	{
		return top==size-1;
	}
	bool isEmpty() const
	{
		return top==-1;
	}
	void makeEmpty()
	{
		top=-1;
	}
	
private:
	int top;
	T *ptr;
	int size;
};
template<class T>
void SeqStack<T>::push(const T item)
{
	if(isFull())
	{
		cout<<"The stack is full!"<<endl;
		exit(1);
	}
	ptr[++top]=item;
}
template<class T>
T SeqStack<T>::pop()
{
	if(isEmpty())
	{
		cout<<"The stack is empty!"<<endl;
		exit(1);
	}
	return ptr[top--];
}
template<class T>
T SeqStack<T>::getTop() const
{
	if(isEmpty())
	{
		cout<<"The stack is empty!"<<endl;
		exit(1);
	}
	return ptr[top];
}
template<class T>
void SeqStack<T>::print() const
{
	if(isEmpty())
	{
		cout<<"The stack is empty!"<<endl;
		exit(1);
	}
	cout<<"Bottom--->";
	for(int i=0;i<=top;i++)
	{
		cout<<ptr[i]<<"--->";
	 } 
	 cout<<"Top"<<endl<<endl<<endl;
}
#endif 

3.链栈的代码实现

#ifndef _LISSTACK_H
#define _LISSTACK_H
#include<iostream>
using namespace std;
template<class T>
class LinkStack
{
public:
	LinkStack():top(NULL){}
	~LinkStack()
	{
		MakeEmpty();
	}
	
	void push(const T item);
	T    pop();
	T    GetTop() const;
	void Print() const;
	
	void MakeEmpty();
	bool IsEmpty() const
	{
		return top==NULL;
	}
	
	
private:
	struct StackNode
	{
		T data;
		StackNode *next;
		StackNode(const T mdata,StackNode *n=NULL):data(mdata),next(n){}
	};
	StackNode *top;
};
template<class T>
void LinkStack<T>::push(const T item) 
{
	top=new StackNode(item,top);
}
template<class T>
T LinkStack<T>::pop()
{
	if(IsEmpty())
	{
		cout<<"The stack is empty!"<<endl;
		exit(1);
	}
	StackNode *tem=top;
	top=top->next;
	T mdata=tem->data;
	delete tem;
	return mdata;
}
template<class T>
T LinkStack<T>::GetTop() const
{
	if(IsEmpty())
	{
		cout<<"The stack is empty!"<<endl;
		exit(1);
	}
	return top->data;
	
}
template<class T>
void LinkStack<T>::Print() const
{
	StackNode *tem=top;
	cout<<"Top--->";
	while(tem!=NULL)
	{
		cout<<tem->data<<"--->";
		tem=tem->next;
	}
	cout<<"Bottom"<<endl<<endl;
}
template<class T>
void LinkStack<T>::MakeEmpty()
{
	StackNode *tem;
	while(top!=NULL)
	{
		tem=top;
		top=top->next;
		delete tem;
	}
}
#endif