mainunit.cpp

C++Builder高级应用开发指南随书源码

#include <iostream>
#include <typeinfo.h>
using namespace std;
class Shape
{
	public:
		Shape(){};
		~Shape(){};
		virtual void Draw(){	//基类的Draw函数
            cout<<"Draw Shape..."<<endl;
        };
};
typedef Shape * pShape;		//定义一个新的指针类型
class Rectangle : public Shape
{
	int left,right,top,bottom;
	public:
		Rectangle(int aleft, int aright, int atop, int abottom){
            left= aleft;
            right= aright;
            top= atop;
            bottom= abottom;
        };
		void Draw(){	//继承类Rectangle的Draw函数，绘制一个矩形
            cout<<"Draw Rectangle..."<<endl;
        };
};
class Circle : public Shape
{
	private:
		int x,y,r;
	public:
		Circle(int ax, int ay, int ar){
            x=ax;
            y=ay;
            r=ar;
        };
		void Draw(){	//继承类Circle的Draw函数，绘制一个圆形
            cout<<"Draw Circle..."<<endl;
        };
		int getR(){		//返回半径的值
			return r;
		};
};
int main(int argc, char* argv[])
{
	const int ShapeNum=30;	//定义一个常量使程序更具有可读性

	pShape ShapeList[ShapeNum];
	for(int i=0;i<ShapeNum;i++)
    {
		if(i %3==0)
			ShapeList[i]= new Shape();
		else if(i %3==1)
			ShapeList[i]= new Rectangle(0+i, 100-i, 0+i, 100-i);
		else if(i%3==2)
			ShapeList[i]=new Circle(100,100,50-i);
    }

	for( int i=0;i<ShapeNum;i++)
	{
		if(typeid(* ShapeList[i])==typeid(Circle))
			cout<<dynamic_cast<Circle *>(ShapeList[i])->getR()<<endl;;

		ShapeList[i]->Draw();	
		delete ShapeList[i];
    }
}