运行下列代码，屏幕上输出
#include <iostream>
using namespace std;
class shape {
protected:
int width,height;
public:
shape(int a = 0, int b = 0) {
width = a;
height = b;
}
virtual int area() {
cout << "parent class area: " << endl;
return 0;
}
};
class rectangle: public shape {
public:
rectangle(int a = 0, int b = 0): shape(a, b) {}
int area() {
cout << "rectangle area: ";
return (width * height);
}
};
class triangle: public shape {
public:
triangle(int a = 0, int b = 0): shape(a, b) {}
int area() {
cout << "triangle area: ";
return (width * height / 2);
}
};
int main() {
shape * pshape;
rectangle rec(10, 7);
triangle tri(10, 5);
pshape = & rec;
pshape -> area();
pshape = & tri;
pshape -> area();
return 0;
}
