1. 实现基类 Shape
2. 实现 Shape 基类子类 两个
3. 实现创建子类对象的工厂类

#include <iostream>
#include <map>
using namespace std;
class Shape //接口
{
public:Shape() {cout << "Shape" << endl;}virtual ~Shape(){cout << "~Shape" << endl;}virtual void draw() = 0;virtual void erase() = 0;
};class Circle :public Shape
{
public:Circle(){cout << "Circle" << endl;}virtual ~Circle(){cout << "~Circle" << endl;}void draw(){cout << "circle::drap" << endl;}void erase(){cout << "circle::erase" << endl;}
};class Square :public Shape
{
public:Square(){cout << "Square" << endl;}virtual ~Square(){cout << "~Square" << endl;}void draw(){cout << "square::drap" << endl;}void erase(){cout << "square::erase" << endl;}
};class ShapeFactory
{
public:ShapeFactory(){cout << "ShapeFactory" << endl;}virtual ~ShapeFactory(){cout << "~ShapeFactory" << endl;}static Shape* createShape(int type){if (type == 0){return new Square();}else {return new Circle();	}}
};//静态成员初始化int main()
{Shape* shape = ShapeFactory::createShape(0);//创建类型shape->draw();shape->erase();shape = ShapeFactory::createShape(1);shape->draw();shape->erase();return 0;
}