C++模板学习之栈的实现

昨天写写了C++  primer上队列的实现，今天在此基础上看看栈的实现。

其中questa.h头文件的内容为：

#ifndef _QUSTA_H
#define _QUSTA_H 1
#include<iostream>

#include<cmath>
#include<cstdlib>
#include<cstring>

#include<string>
/**顺序容器**/
#include<vector>
#include<list>
#include<deque>
#include<stack>
#include<queue>
/**关联容器**/
#include<bitset>
#include<utility>
#include<set>
#include<map>
/**泛型算法**/
#include<algorithm>
#include<numeric>
/*异常处理*/
#include<exception>
#include<stdexcept>
using namespace std;
#endif

栈为了实现出栈的要求，这里使用了双向链表，栈的模板类如下：

#ifndef _STACK_H
#define _STACK_H 1
#include"questa.h"

template<class type> class stackc;
template <class type> ostream& operator<<(ostream&,const stackc<type>&);
template<class type> class stackcitem{
	type data;
	stackcitem *prev;
	stackcitem *next;
	friend class stackc<type>;
	friend ostream& operator<< <type>(ostream&, const stackc<type>&);
	stackcitem():data(type()),prev(0),next(0){}
	stackcitem(const type &t):data(t),prev(0),next(0){}
};
template<class type> class stackc{
private:
	stackcitem<type> *headnode;
	stackcitem<type> *tailnode;
	int count;
public:
	stackc():count(0){
		cout<<"construct stack..."<<endl;
	    initstack();
	}
	void initstack();
	void push(const type&);
	type pop();
	int stack_len();
	void cleanstack();
	friend ostream& operator<< <type>(ostream&, const stackc<type>&);
	inline bool isempty()
	{
		return tailnode==0;
	}
	~stackc(){
		cleanstack();
	}
};
template<class type> void stackc<type>::initstack()
{
	cout<<"init stack..."<<endl;
	stackcitem<type> *node;
	node=new stackcitem<type>;
	cout<<"build stack node ok..."<<endl;
	if(NULL==node)
	{
		cerr<<"no memory..."<<endl;
		exit(1);
	}
	headnode=tailnode=node;
}
template<class type> void stackc<type>::push(const type &data)
{
	stackcitem<type> *node;
	node=new stackcitem<type>(data);
	if(NULL==node)
	{
		cerr<<"no memory..."<<endl;
		exit(1);
	}

	tailnode->next=node;
	node->prev=tailnode;
	tailnode=node;
	++count;
}
template<class type> type stackc<type>::pop()
{
	    stackcitem<type> *p=tailnode;
		type  value=p->data;
		p=p->prev;
		delete tailnode;
		tailnode=p;
		--count;
		return value;
}
template<class type> void stackc<type>::cleanstack(){
	while(!isempty())
		pop();
}
template<class type> int stackc<type>::stack_len(){
	return count;
}
template <class type> ostream& operator<< <type> (ostream &os, const stackc<type> &q) 
 {
	 os <<"{*";
      stackcitem<type> *p;
      for(p=q.headnode->next;p;p=p->next)
           os <<p->data<<",";
	  os<<"*}";
      return os;
 }
#endif

这个模板类主要实现入栈push、出栈pop，清空栈cleanstack、压入栈的元素个数stack_len、输出栈内元素重载运算符<<。

测试程序：

#include"questa.h"
#include"queue.h"
#include"stack.h"

int main()
{
	stackc<string> s;
	s.push("hello");
	s.push("world!");
	cout<<s.stack_len()<<":"<<s<<endl;
	while(!s.isempty())
		cout<<s.pop()<<endl;
}