#include <iostream>
#include <cmath>
using namespace std;


class Shape
{
public:
    virtual Shamename() const=0;
    virtual area() const=0;
};


class Circle:public Shape
{
public:
    Circle(double r):radius(r) {}
    virtual Shamename() {cout<<"Circle:"<<endl;}
    virtual double area(){return 3.1415926*radius*radius;}
protected:
    double radius;
};
class Rectangle:public Shape
{
public:
    Rectangle(double a,double b):length(a),with(b) {}
    virtual Shamename(){cout<<"Rectangle:"<<endl;}
    double area() {return length*with;}
protected:
    double length,with;
};
class Triangle:public Shape
{
public:
    Triangle(double a,double b,double c):bord1(a),bord2(b),bord3(c) {}
    virtual Shamename(){cout<<"Rectangle:"<<endl;}
    double area()
    {
        double s=(bord1+bord2+bord3)/2;
        return sqrt(s*(s-bord1)*(s-bord2)*(s-bord3));
    }
protected:
    double bord1,bord2,bord3;
};
void printArea(const Shape &s)
{
    cout<<s.Shamename()<<endl;
    cout<<s.area()<<endl;
}
void main()
{
      Circle c1(2);
      printArea(c1);
}
错在哪里啊

子类重载也要加上const

亲 俺咋觉得一点都布简单啊

我们期末考试编程题的复杂版。。。。这都能见到

丢三落四的，语法不熟练是其中一个原因，但性格马虎才是主要的原因

#include <cmath>

class Shape
{
public:
    virtual const char* Shamename() const = 0;
    virtual double area() const = 0;
};

class Circle : public Shape
{
public:
    explicit Circle(double r) : radius(r) {}
    virtual const char* Shamename() const { return "Circle"; }
    virtual double area() const { return 3.1415926*radius*radius; }
protected:
    double radius;
};

class Rectangle : public Shape
{
public:
    Rectangle(double a,double b) : length(a),with(b) {}
    virtual const char* Shamename() const { return "Rectangle"; }
    virtual double area() const { return length*with; }
protected:
    double length,with;
};

class Triangle : public Shape
{
public:
    Triangle(double a,double b,double c):bord1(a),bord2(b),bord3(c) {}
    virtual const char* Shamename() const { return "Triangle"; }
    virtual double area() const
    {
        double s=(bord1+bord2+bord3)/2;
        return sqrt(s*(s-bord1)*(s-bord2)*(s-bord3));
    }
protected:
    double bord1,bord2,bord3;
};

#include <iostream>

void printArea( const Shape& s )
{
    std::cout << s.Shamename() << std::endl;
    std::cout << s.area() << std::endl;
}

using namespace std;

int main()
{
    Circle c1(2);
    printArea(c1);

    return 0;
}

楼上似乎已经解决了，我就不看了，来混分的

5楼解决你问题了，过来混个分！！注意细节，还有就是书写格式，放别自己也方便他人查看！