/*求球，圆柱，圆锥的体积和面积*/
#include<iostream>
using namespace std;
const double Pi=3.14;
class ball
{protected:
int r;
public:
voidsetdata()
   {
    cout<<"please enter the r:"<<endl;
    cin>>r;
   }
intgetR()
   {
    return r;
   }
double volume()
   {
double v;
     v=4/3*Pi*getR()*getR()*getR();
    return v;
   }
};
classyuan : public ball
{private:
int h;
public:
void input()
   {
    setdata();
    cout<<"please enter the h:"<<endl;
    cin>>h;
   }
double volume()
   {
double v;
     v=Pi*getR()*getR()*h;
    return v;
   }
};
classzhui : public yuan
{public:
void input()
   {
    setdata();
   }
double volume()
   {
double v;
     v=1/3*Pi*getR()*getR()*h;
    return v;
   }
private:

};
int main()
{
ball b;
b.setdata();
cout<<"the volume of ball is:"<<endl;
cout<<b.volume();
yuan y;
y.input();
cout<<"the volume of yuan is:"<<endl;
cout<<y.volume();
zhui z;
z.input();
cout<<"the volume of zhui is:"<<endl;
cout<<z.volume();
return 0;

}


E:\\jiue\jiejie.cpp(50) : error C2248: 'h' : cannot access private member declared in class 'yuan'
        E:\\jiue\jiejie.cpp(26) : see declaration of 'h'
执行 cl.exe 时出错.

jiue.exe - 1 error(s), 0 warning(s)

#include<iostream>
using namespace std;
const double Pi=3.14;
class yuan{
    protected:
      int r;
    public:
      void setdata(){
         cout<<"\nplease enter the r:"<<endl;
         cin>>r;
     }
     int getR(){
          return r;
     }
     double getArea(){
         return Pi*r*r;
    }
};
class  ball: public yuan{
  public:
     void input(){
         setdata();
    }
    double volume(){
        double v;
        v=4*Pi*getR()*getR()*getR()/3;
        return v;
   }
};
class zhui : public yuan{
    public:
      void input(){
         setdata();
         cout<<"please enter the h:"<<endl;
         cin>>h;
      }
      double volume(){
         double v;
         v=getArea()*h/3;
         return v;
      }
    private:
      int h;
};
int main(){
yuan y;
cout<<"yuan :";
y.setdata();
cout<<"the area of yuan is:"<<endl;
cout<<y.getArea()<<endl;
zhui z;
cout<<"zhui";
z.input();
cout<<"the volume of zhui is:"<<endl;
cout<<z.volume()<<endl;
ball b;
cout<<"ball";
b.input();
cout<<"the volume of ball is:"<<endl;
cout<<b.volume()<<endl;
return 0;
}

楼主的yuan类里面的h成员为私有，不能被派生类调用的，一定是因为zhui类的Input函数和volume函数调用了h才导致报错。试试把yuan类的h改成protected看成不成。另外注意一下，你的zhui类继承了Input函数，但又另写了一个，有可能会让你输入两次半径哦。

对的，我一开始没写圆锥时调试时就要输入两次半径= =。那现在圆锥那部分要继承哪一个啊，再给点意提示哈，原谅我脑子笨= =

谢谢哈，我电脑上没有VC++不好调试，等到机房再试试= =。阿里嘎倒

为了逻辑上看起来更明白，建议还是让zhui去继承ball吧，r的参数从ball类得到，h参数作为zhui私有的。还有，如果zhui和ball当中计算体积的函数重名，当把ball的volume定性为virtual

好的，知道啦，谢谢==嘿嘿