用兩個棧實現隊列

//用兩個棧實現隊列，實現在隊尾添加元素和在隊列頭部刪除元素
#include <iostream>

using namespace std;

const int DEPTH = 20;	//定義棧的深度

template <class T> struct stack		//定義棧模版
{
	int top;	//棧頂指針
	T S[DEPTH];		//定義一個數組存儲棧中數據
	bool push(T member)
	{
		if (top >= 20)
		{
			throw ("棧已滿！");
		}
		S[top] = member;
		top++;
	}
	T pop()
	{
		if (0 >= top)
		{
			throw ("棧爲空！");
		}
		top--;
		return S[top];
	}
};

template <class T> class CQueue		//定義隊列模版
{
public:
	CQueue(void);
	~CQueue(void);

	void appendTail(const T& node);	//隊尾添加元素
	T deleteHead();			//隊頭刪除元素

private:
	stack<T> stack1;
	stack<T> stack2;
};

template <class T>
CQueue<T>::CQueue(void)
{
	stack1.top = 0;
	stack2.top = 0;
}

template <class T>
CQueue<T>::~CQueue(void)
{
}

template <class T>
void CQueue<T>::appendTail(const T& node)
{
	try
	{
		stack1.push(node);
	}
	catch(char *e)
	{
		cout << "隊列已滿！" << endl;
	}
	
}

template <class T>
T CQueue<T>::deleteHead()
{
	int size2 = stack2.top;	//stack1中的元素個數
	if (size2 == 0)
	{
		int temp = stack1.top;
		if (temp == 0)
		{
			throw ("隊列已空！");
		}
		for (int i=0; i<temp; i++)
		{
			stack2.push(stack1.pop());
		}
	}
	
	return stack2.pop();
}

int main()
{
	CQueue<int> que;
	try
	{
		for (int i=0; i<21; i++)
		{
			que.appendTail(i);
		}
		for (int i=0; i<21; i++)
		{
			cout << que.deleteHead() << " ";
		}
	}
	
	catch (char *e)
	{
		cout << e << endl;
	}

	return 0;
}