GESP 2024年6月 C++六级 单选题 第3题

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();
}

• A. rectangle area: triangle area:
• B. parent class area: parent class area:
• C. 运行时报错
• D. 编译时报错

正确答案：A