#include<iostream> using namespace std; class CPoint { private: double x,y; public : CPoint (double i,double j); double Getx(); double Gety(); double Setpoint(double i,double j); }; class CShape { public: CPoint point; virtual double Area() { return 0.0; } }; class CCircle:public CShape { public: float r; CCircle(CPoint p1,float r=2):CShape(),r(r){} double Area() { return 3.14*r*r; } }; class CRect:public CShape { public: double x,y; CRect(CPoint p1,double x=2,double y=1):CShape(),x(x),y(y){} double Area() { return x*y; } }; class CEll:public CShape { public: double x,y; CEll(CPoint p1,double x=2,double y=1):CShape(),x(x),y(y){} double Area() { return 3.14*x*y; } }; int main() { return 0; }In constructor 'CCircle::CCircle(CPoint, float)': /storage/emulated/0/Code/Project/CPlusPlus/作业3/main.cpp:26:46: error: use of deleted function 'CShape::CShape()' CCircle(CPoint p1,float r=2):CShape(),r(r){} ^ compilation terminated due to -Wfatal-errors. 怎么修改？

在CShape的构造函数中添加一个默认构造函数即可。代码如下：

#include<iostream> 
using namespace std; 

class CPoint { 
private:     
    double x,y; 
public :     
    CPoint (double i,double j);     
    double Getx();     
    double Gety();     
    double Setpoint(double i,double j); 
}; 

class CShape { 
public:     
    CPoint point;
    CShape(){} // 添加默认构造函数
    virtual double Area()     
    {         
        return 0.0;     
    } 
}; 

class CCircle:public CShape { 
public:     
    float r;     
    CCircle(CPoint p1,float r=2):CShape(),r(r){}     
    double Area()     
    {         
        return 3.14*r*r;     
    } 
}; 

class CRect:public CShape { 
public:     
    double x,y;     
    CRect(CPoint p1,double x=2,double y=1):CShape(),x(x),y(y){}     
    double Area()     
    {         
        return x*y;     
    } 
}; 

class CEll:public CShape { 
public:     
    double x,y;     
    CEll(CPoint p1,double x=2,double y=1):CShape(),x(x),y(y){}     
    double Area()     
    {         
        return 3.14*x*y;     
    } 
}; 

int main() {     
    return 0; 
}