C++第三次实验

28班朱骅08210763
//1、声明一个Shape抽象类，在此基础上派生出Rectangule和Circle类，二者同时利用GetArea（）函数计算对象的面积，GetPerim（）函数计算对象的周长
#include "iostream.h"
#define pi 3.1415 //define the const variable pi
class Shape
{
public:
virtual double GetArea()=0; //the statement of the pure virtual function
virtual double GetPerim()=0;
};
class Rectangle : public Shape //the definition of the pure virtual function {
public:
double GetArea ();
double GetPerim();
Rectangle(double x,double y); //the construtor of the rectangle class with parameters
private:
double length,width;
};
Rectangle::Rectangle(double x,double y)
{
length =x;
width =y;
}
double Rectangle :: GetArea () //the definition of the function
{
return (length * width);
}
double Rectangle :: GetPerim () //the definition of the function
{
return (2*(length + width));
}
class Circle : public Shape
{
public:
double GetArea ();
double GetPerim();
Circle(double r); //the construtor of the rectangle class with parameters
private :
double radius;
};
Circle::Circle(double r)
{
radius = r;
}
double Circle::GetArea() //the definition of the function
{
return (pi*radius*radius);
}
double Circle::GetPerim() //the definition of the function
{
return (2*pi*radius);
}
void main()
{
Rectangle * re=new Rectangle(3.4,5.6);
Circle * cr= new Circle(2.5);
double s,t,m,n;
s =re->GetArea();
t =re->GetPerim();
cout<<"the area of the rectangle："<<endl;
cout<<s<<endl;
cout<<"the perim of the rectangle："<<endl;
cout<<t<<endl;
m =cr->GetArea();
n =cr->GetPerim();
cout<<"the area of the circle："<<endl;
cout<<m<<endl;
cout<<"the perim of the circle："<<endl;
cout<<n<<endl;
}
//2、有一种栈，这种栈是按数组索引减小的方向增长的。

初始时栈为空且top=21.往栈中压入3个字符后，索引top=18，
//栈顶元素为list[top]=C.在这个栈模型中，索引top在每次push后索引操作后减小，而在top
操作后则增大。

用此模型实现stack类模板并编写测试程序。

#include "iostream.h"
#include "string"
#define NULL 0
template <class T> class Stack //define the template of the class stack
{
public:
Stack(){top=21;}
void push(T s);
T pop();
private:
int top;
T list[21];
};
class Stack<char *> //to cope with the special situation ---char *
{
public:
Stack(){top=21;int i;for(i=0;i<21;i++){list[i]=new char;} }
void push(char * s);
char * pop();
~Stack()
{
for(int i=0;i<21;i++)
{
list[i]=NULL;
delete list[i]; //free off the space of the array
}
}
private:
int top;
char * list[21];
};
template <class T>void Stack<T>::push(T s) //the definition of the function
{
if (top <= 0)
cout<<"Sorry,the stack is full!"<<endl;
list[--top] = s;
}
template <class T> T Stack<T>::pop()
{
if (top > 21)
cout<<"Sorry,the stack is empty!"<<endl;
cout<<list[top]<<endl;
return (list[top++]);
}
void Stack<char *>::push(char * s)
{
if (top <= 0)
cout<<"Sorry,the stack is full!"<<endl;
strcpy(list[--top],s);
}
char * Stack<char *>::pop()
{
if (top > 21)
cout<<"Sorry,the stack is empty!"<<endl;
cout<<list[top]<<endl;
return (list[top++]);
}
void main()
{
Stack<char> stack;
stack.push('A'); //push in a character
stack.push('B');
stack.push('C');
stack.pop();
stack.pop();
stack.pop();
Stack<char *> s;
s.push("ABC"); //push in a string
s.pop();
}。