填空题
如下程序声明了一个二维图形类TwoDShape，从其派生出矩形类Rec。
#include＜iostream＞
#include＜string＞
using namespaee std,
class TwoDShape{// 二维图形类
char name[20];
public:
TwoDShape (char * n="unknown") {
strcpy(name, n);
}
Char * getName(){return name;}
【14】 =0;
};
class Rec: public TwoDShape{
double width, height
public:
Rec(double w-=0. 0,double h=0. 0):TwoDShape("rectangle")
{ width=w; height=h; }
double getWidth() {return width;}
double getHeight() {return height;}
double area() {return width * height;}
};
int main() {
TwoDShape * shape;
Shape=new Rec(2.1,3.0);
cout＜＜"object is"＜＜shape-＞getName()＜＜"\n";
cout＜＜"Area is"＜＜shape-＞area()＜＜"\n";
return 0
}
请将程序补充完整，使程序在运行时输出：
abject is triangle
Area is 6.3
【参考答案】
virtual double area()