C++ 抽象类与继承：圆形和正方形面积计算

#include using namespace std;

class AbstractC{ public: virtual double area() = 0; };

class Circle : public AbstractC{ private: double radius; public: Circle(double r){ radius = r; } void setRadius(double r){ radius = r; } double getRadius(){ return radius; } double area(){ return 3.14 * radius * radius; } };

class Square : public AbstractC{ private: double side; public: Square(double a){ side = a; } void setSide(double a){ side = a; } double getSide(){ return side; } double area(){ return side * side; } };

int main(){ Circle c(5); Square s(5);

cout << "Circle Area: " << c.area() << endl;
cout << "Square Area: " << s.area() << endl;

return 0;

}