usestack.cpp

我学习C++ Primer Plus过程中写下的课后作业的编程代码

/*
4.请看下面程序清单10.10定义的Stack类的变量:
stack.h -- class declaration for the stack ADT

typedef unsigned long Item;

class Stack
{
private:
	enum {MAX = 10};		//constant specific to class
	Item * pitems;			// holds stack items
	int size;				// number of elements in stack
	int top;				// index for top stack item
public:
	Stack(int n = 10);		// crates stack with n elements
	Stack(const Stack & st);
	~Stack();
	bool isempty()const;
	bool isfull()const;
	// push() returns false if stack already is full, true otherwise
	bool push(const Item & item);	// add item to stack
	// pop() returns false if stack already is empty, true otherwise
	bool pop(Item & item);			// pop top into item
	Stack & operator = (const Stack & st);
};

正如私有成员表明的,这个类使用动态分配的数组堆栈项.请重新编写方法,以适应这
种新的表示法,并编写一个程序来演示所有的方法,包括复制构造函数和赋值操作符.
*/

// stacker.cpp -- testing the Stack class
#include <iostream>
#include <cctype>
#include "stack.h"
int main()
{
	using namespace std;
	Stack st;
	char ch;
	unsigned long po;
	cout<<"Please enter A to add a purchase order.\n"
		<<"P to process a po, or Q to quit.\n";
	while( cin>>ch && toupper(ch) != 'Q')
	{
		while( cin.get() != '\n')
			continue;
		if ( !isalpha(ch) )
		{
			cout<<'\a';
			continue;
		}
		switch(ch)
		{
		case 'A':
		case 'a':	
			cout<<"Enter a PO number to add:";
			cin>>po;
			if( st.isfull() )
				cout<<"stack already full\n";
			else
				st.push(po);
			break;
		case 'P':
		case 'p':	
			if( st.isempty() )
				cout<<"stack already empty\n";
			else
			{
				st.pop(po);
				cout<<"PO #"<<po<<" popped\n";
			}
			break;
		}
		cout<<"Please enter A to add a purchase order.\n"
		    <<"P to process a po, or Q to quit.\n";
	}
	cout<<"st2 = st:\n";
	Stack st2 = st;
	while( !st2.isempty() )
	{
		cout<<"pop: ";
		st2.pop(po);
		cout<<po<<endl;
	}
	cout<<"Bye\n";
	return 0;
}