关于类的问题，求解答

Question

上述三个类，都有一个自我介绍函数printme（）,在各函数中分别输出..

Answer 1

如下：

#include <iostream>
using namespace std;

class CShape
{
public:
    virtual void printArea() = 0;
    void printMe() { cout << "I am CShape" << endl; }
};

class CCircle :public CShape
{
private:
    double radius;
public:
    CCircle(double r) { radius = r; }
    void printArea() { cout <<"面积："<< 3.1415926 * radius * radius; }
    void printMe() { cout << "I am CCircle" << endl; }
};

class CRectangle :public CShape
{
private:
    double length, width;
public:
    CRectangle(double l, double w) { length = l; width = w; }
    void printArea() { cout << "面积：" << length*width; }
    void printMe() { cout << "I am CRectangle" << endl; }
};

int main()
{
    CCircle c(2);
    c.printMe();
    c.printArea();
    CRectangle r(3, 4);
    r.printMe();
    r.printArea();
    return 0;
}