有以下程序： #include ＜iostream＞ using namespace std; #define PI 3.14 class Point { private: int x,y; public: Point(int a,int b) { x=a; y=b; } int getx() { return x; } int gety() { return y; } }; class Circle: public Point { private: int r; public: Circle(int a, int b,int c):Point(a,b) { r=c; } int getr() { return r; } double area() { return PI*r*r; } }， int main() { Circle c1(5,7,10); cout＜＜c1 .area()＜＜endl; return0； } 程序执行后的输出结果是