码图：67 C++Test

题目描述：

通过课程进入 题 号: 67 C++Test_Shape 语言要求： C++ 已知基类定义在头文件ShapeFactory.h中，类定义如下：

#pragma once class ShapeFactory { public: ShapeFactory(){}; virtual ~ShapeFactory(){}; virtual float Circumstance(){return 0;}; ShapeFactory *Create(float a,float b,float c); ShapeFactory *Create(float a,float b,float c,float d); ShapeFactory *Create(float r); };

请写出三角形、四边形、圆形三个派生类，构造函数分别传入三边/四边/半径的长度（不用检查是否符合三角形、矩形、圆的条件，没有异常输出），重写出求周长的函数（Circumstance函数）。 然后实现基类的Create函数，这里重载的三个Create函数，分别生成三角形、四边形、圆形的对象。 比如三角形类为Triangle：

ShapeFactory * ShapeFactory::Create(float a,float b,float c) { ShapeFactory *p=new Triangle(a,b,c); return p; }

实现：

#include<iostream> #include"ShapeFactory.h" using namespace std; class Triangle :public ShapeFactory { private: float a, b, c; public: Triangle(float a0, float b0, float c0) { a = a0; b = b0; c = c0; } float Circumstance() { return a + b + c; } }; class Quadrangle :public ShapeFactory { private: float a, b, c, d; public: Quadrangle(float a0, float b0,float c0,float d0) { a = a0, b = b0, c = c0, d = d0; } float Circumstance() { return a + b + c+d; } }; class Circle :public ShapeFactory { private: float r; public: Circle(float r0) { r = r0; } float Circumstance() { return r*2*3.14; } }; ShapeFactory* ShapeFactory::Create(float a, float b, float c) { ShapeFactory* p = new Triangle(a, b, c); return p; } ShapeFactory* ShapeFactory::Create(float a, float b, float c, float d) { ShapeFactory* p = new Quadrangle(a, b, c, d); return p; } ShapeFactory* ShapeFactory::Create(float r) { ShapeFactory* p = new Circle(r); return p; }