第十三周實驗報告三

<span style="font-size:18px;">//【任務】寫一個程式，定義抽象基類Shape，由它派生出個衍生類別，Circle（圓形）、Rectangle（矩形）、Triangle（三角形）。用如下的mian()函數，求出定義的幾個幾何體的面積和。</span>  

來源程式及運行結果

 

<span style="font-size:18px;">#include<iostream>#define pi 3.14using namespace std;class Shape{public:virtual double Area() = 0;};class Circle: public Shape{private:double radius;public:Circle(double r):radius(r){};double Area();};double Circle::Area(){return (pi * radius * radius);}class Rectangle: public Shape{private:double length;double width;public:Rectangle(double l,double w):length(l),width(w){};double Area();};double Rectangle::Area(){return (length * width);}class Triangle:public Shape{private:double base;double height;public:Triangle(double b,double h):base(b),height(h){};double Area();};double Triangle::Area(){return ((base * height)/2);}int main(){Circle c1(12.6),c2(4.9);    //建立Circle類對象c1,c2,參數為圓半徑Rectangle r1(4.5,8.4),r2(5.0,2.5);       //建立Rectangle類對象r1,r2,參數為矩形長、寬Triangle t1(4.5,8.4),t2(3.4,2.8);    //建立Triangle類對象t1,t2，參數為三角形底邊長與高Shape *pt[6]={&c1,&c2,&r1,&r2,&t1,&t2}; //定義基類指標數組pt，各元素指向一個衍生類別對象double areas=0.0;      //areas為總面積for(int i=0; i<6; i++){areas=areas+pt[i]->Area();}cout<<"totol of all areas="<<areas<<endl;   //輸出總面積system("pause");return 0;}運行結果：totol of all areas=647.858請按任意鍵繼續. . .</span>