面向对象上机考试题—关于堆栈

//建立一个栈类，能够存放图形元素（矩形或圆形），有入栈，出栈。

　　//取栈顶的功能。建立元素类，里面至少一个纯虚函数，矩形和圆形类。

　　//来实现里面的函数SHOWME，实现他的显示图形信息的功能。重载>>.

　　//能够输入图形信息。测试以上类的功能。

#include "stdafx.h"
#include "iostream.h"
#include "string.h"
const n=50;
class shape
{
protected:
double width, length;
public:
shape() {}
virtual void ShowMe()=0;
};
class rectangle:public shape
{
public:
rectangle():shape(){}
friend istream &operator>>(istream &is, rectangle &rec)
{
cout<<"请输入长方形的长：";
is>>rec.length;
cout<<"请输入长方形的宽：";
is>>rec.width;
return is;
}
void ShowMe()
{
cout<<"长方形的长宽分别为：("< <<","< }
};
class circle:public shape
{
private:
//double x, y;
double r;
public:
circle():shape()
friend istream &operator>>(istream &is, circle &cir)
{
cout<<"请输入圆的圆心坐标(x,y)：";
is>>cir.width;
is>>cir.length;
cout<<"请输入圆的半径：";
is>>cir.r;
return is;
}
void ShowMe()
{
cout<<"圆的圆心坐标为：("< <<" 半径为："< }
};
class stack
{
shape *sp[n];
rectangle rec[n];
circle cir[n];
int size;
public:
stack()
{
for (int i=0; i sp[i]=NULL;
size=-1;
}
bool empty(){return size==-1;}
bool full(){return size==n-1;}
void push(rectangle &rect)
{
rec[++size]=rect;
sp[size]=new rectangle;
sp[size]=&rec[size];
}
void push(circle &circ)
{
cir[++size]=circ;
sp[size]=new circle;
sp[size]=&cir[size];
}
void top()
{
if (empty()) cout<<"栈为空"< else {
cout<<"栈顶元素为:"< sp[size]->ShowMe();
}

}
void pop()
{
if (empty()) cout<<"栈为空"< else {
cout<<"出栈元素为:"< sp[size--]->ShowMe();
}
}
};
void main()
{
stack Stack;
rectangle rec;
circle cir;
int s=1;
while (s)
{
cout< cout<<"请选择1-5号键*作"< cout<<" 1: 矩形进栈;"< cout<<" 2: 圆进栈;"< cout<<" 3: 显示栈顶元素;"< cout<<" 4: 出栈;"< cout<<" 5: 退出程序;"< cin>>s;
switch(s)
{
case 1: cin>>rec; Stack.push(rec); break;
case 2: cin>>cir; Stack.push(cir); break;
case 3: Stack.top(); break;
case 4: Stack.pop(); break;
case 5: s=0; break;
//default: cout<<"请重新输入"< }
}
}