下列代码中，s1->draw(); 和 s2->draw(); 输出不同结果的主要原因是（）。
class Shape {
public:
virtual void draw() {
cout << "绘制图形" << endl;
}
virtual ~Shape() {}
};
class Circle : public Shape {
public:
void draw() override {
cout << "绘制圆形" << endl;
}
};
class Rectangle : public Shape {
public:
void draw() override {
cout << "绘制矩形" << endl;
}
};
int main() {
Shape* s1 = new Circle();
Shape* s2 = new Rectangle();
s1->draw();
s2->draw();
delete s1;
delete s2;
return 0;
}
- A.
draw()是普通成员函数 - B.
Shape中的draw()被声明为虚函数 - C.
Circle和Rectangle中使用了public继承 - D. 指针变量名不同