介紹

棧是一種線性結構，它有以下幾個特點：

1）棧中資料是按照“後進先出”方式進出棧的

2）向棧中新增/刪除資料時，只能從棧頂進行操作

棧通常包括三種操作：top、pop、push

top -- 返回棧頂元素

pop -- 返回並刪除棧頂元素

push -- 向棧中新增元素

常見錯誤：棧空時進行top或pop操作

解決方法：使用者在使用top或pop操作時，需確保棧是非空的

————————————————————————————————————————————————————————————————————————————

棧的示意圖

出棧

入棧

棧的C++實現

順序棧

順序棧結構實現的標頭檔案SeqStack.h

#ifndef SeqStack_byNim
#define SeqStack_byNim

#include<iostream>
using namespace std;

const int MAX_SIZE=100;

template <class T>
class SeqStack
{
	private:
		T *data;
		int topPointer;
	public:
		SeqStack();
		~SeqStack();
		
		void push(T e);
		T pop();
		T top();
		
		bool empty();
};

template <class T>
SeqStack<T>::SeqStack()
{
	topPointer=-1;
	data=new T[MAX_SIZE];
}

template <class T>
SeqStack<T>::~SeqStack()
{
	topPointer=-1;
	delete []data;
}

template <class T>
void SeqStack<T>::push(T e)	//入棧操作
{
	if(topPointer==MAX_SIZE-1)		
	{
		cout<<"OVERFLOW"<<endl;			return;
	}
	topPointer++;
	data[topPointer]=e;
}

template <class T>
T SeqStack<T>::pop()	//出棧操作 
{
	if(topPointer==-1)
	{
		throw "棧空";
	}
	return data[topPointer--];
}

template <class T>
T SeqStack<T>::top()
{
	if(topPointer==-1)
	{
		throw "棧空";
	}
	return data[topPointer];
}

template <class T>
bool SeqStack<T>::empty()
{
	if(topPointer==-1)
	{
		return true;
	}
	return false;
}

#endif
 

測試檔案：SStackTest.cpp

#include<iostream>
#include "SeqStack.h"
using namespace std;

int main()
{
	int tmp = 0;
	SeqStack<int> *astack = new SeqStack<int>;
	
	cout<<"main"<<endl;
	
	//將10, 20, 30 依次推入棧中
	astack->push(10);
    astack->push(20);
    astack->push(30);
    
    // 將“棧頂元素”賦值給tmp，並刪除“棧頂元素”
    tmp = astack->pop();
    cout<<"tmp="<<tmp<<endl;
    
    // 只將“棧頂”賦值給tmp，不刪除該元素
    tmp = astack->top();
    cout<<"tmp="<<tmp<<endl;
    
    astack->push(40);
    
    while(!astack->empty())
    {
    	tmp = astack->pop();
    	cout<<"tmp="<<tmp<<endl;
	}
	return 0;
}
 

鏈棧

鏈棧結構實現的標頭檔案：LinkStack.h

#ifndef LinkStack_byNim
#define LinkStack_byNim

#include<iostream>
using namespace std;

template<class T>
struct Node
{
	T data;	//資料域 
	Node *next;	//指標域 
};

template<class T>
class LinkStack
{
	private:
		Node<T> *topPointer;
	public:
		LinkStack();
		~LinkStack();
		
		void push(T e);
		T pop();
		T top();
		
		bool empty();
};

template<class T>
LinkStack<T>::LinkStack()
{
	topPointer=new Node<T>;
	topPointer->next=NULL;
}	

template<class T>	
LinkStack<T>::~LinkStack()
{
	delete topPointer;
}

template<class T>
void LinkStack<T>::push(T e)
{
	Node <T> *aNode;
	aNode=new Node<T>;
	aNode->data=e;
	aNode->next=topPointer;
	topPointer=aNode;
}

template<class T>
T LinkStack<T>::pop()
{
	if(topPointer==NULL)
		throw "下溢";
	Node <T> *p;
	p=topPointer;
	T rtndata = topPointer->data;
	topPointer=topPointer->next;
	delete p;
	return rtndata;
}

template<class T>
T LinkStack<T>::top()
{
	if(topPointer==NULL)
		throw "Empty";
	return topPointer->data;
}

template<class T>
bool LinkStack<T>::empty()
{
	if(topPointer==NULL)
		return true;
	return false;
}

#endif

測試檔案：LStackTest.cpp

#include<iostream>
#include "LinkStack.h"
using namespace std;

int main()
{
	string tmp;
	LinkStack<string> *astack = new LinkStack<string>;
	
	cout<<"main"<<endl;
	
		//將"cat"、"dog"、"pig"依次推入棧中
	astack->push("cat");
    astack->push("dog");
    astack->push("pig");
    
    // 將“棧頂元素”賦值給tmp，並刪除“棧頂元素”
    tmp = astack->pop();
    cout<<"tmp="<<tmp<<endl;
    
    // 只將“棧頂”賦值給tmp，不刪除該元素
    tmp = astack->top();
    cout<<"tmp="<<tmp<<endl;
    
    astack->push("duck");
    
    while(!astack->empty())
    {
    	tmp = astack->pop();
    	cout<<"tmp="<<tmp<<endl;
	}
	return 0;
}

STL中自帶的“棧”

標頭檔案：#include <stack>

測試檔案：StackTest.cpp

#include<iostream>
#include<stack>
using namespace std;

int main()
{
	int tmp = 0;
	stack<int> *astack = new stack<int>;
	
	cout<<"main"<<endl;
	
	//將10, 20, 30 依次推入棧中
	astack->push(10);
    astack->push(20);
    astack->push(30);
    
    // 刪除“棧頂元素”，pop操作不返回棧頂資料 
    astack->pop();
    cout<<"tmp="<<tmp<<endl;
    
    // 只將“棧頂”賦值給tmp，不刪除該元素
    tmp = astack->top();
    cout<<"tmp="<<tmp<<endl;
    
    astack->push(40);
    
    while(!astack->empty())
    {
    	tmp = astack->top();
    	cout<<"tmp="<<tmp<<endl;
    	astack->pop();
	}
	return 0;
}