初学
题目描述:
类的继承:
编写程序求球,圆柱的表面积和体积。
(1)定义基类圆,至少含有一个数据成员半径
(2)定义基类的派生类:球,圆柱都含有求表面积和体积的成员函数和输出函数
(3)在main中求解球,圆柱的表面积和体积
父类Circle.h:
class Circle
{
public:
Circle(double r);
protected:
double C_r;
};
Circle.cpp
#include"Circle.h"
Circle::Circle(double r)
{
C_r=r;
}
子类(1)Ball.h:
#include"Circle.h"
class Ball:public Circle
{
public:
Ball(double r,double area,double volume);
double area(double r);
double volume(double r);
void B_show();
protected:
double B_area;
double B_volume;
};
Ball.cpp:
#include"Ball.h"
#include
using namespace std;
Ball::Ball(double r,double area,double volume):Circle®
{
B_area=area;
B_volume=volume;
}
double Ball::area(double C_r)
{
B_area=43.14C_rC_r;
return B_area;
}
double Ball::volume(double C_r)
{
B_volume=3.144/3C_rC_rC_r;
return B_volume;
}
void Ball::B_show()
{
cout<<“面积为:”<<B_area<<“体积为:”<<B_volume<<endl;
}
子类(2)Cylinder.h
#include"Circle.h"
class Cylinder:public Circle
{
public:
Cylinder(double r,double area,double volume,double h);
double area(double r,double h);
double volume(double r,double h);
void C_show();
protected:
double C_area;
double C_volume;
double C_h;
};
Cylinder.cpp:
#include"Cylinder.h"
#include
using namespace std;
Cylinder::Cylinder(double r,double area,double volume,double h):Circle®
{
C_area=area;
C_volume=volume;
C_h=h;
}
double Cylinder::area(double C_r,double C_h)
{
C_area=23.14C_rC_h+23.14C_rC_r;
return C_area;
}
double Cylinder::volume(double C_r,double C_h)
{
C_volume=3.14C_rC_rC_h;
return C_volume;
}
void Cylinder::C_show()
{
cout<<“面积为:”<<C_area<<“体积为:”<<C_volume<<endl;
}
demo.cpp:
#include"Ball.h"
#include"Cylinder.h"
#include"stdlib.h"
int main()
{
Ball b1(0,0,0);
b1.area(5);
b1.volume(5);
b1.B_show();
Cylinder c1(0,0,0,0);
c1.area(5,2);
c1.volume(5,2);
c1.C_show();
system(“PAUSE”);
return 0;
}
我刚做完Ball的时候程序可以正常运行,然后将Ball的内容复制后改写为Cylinder,两个子类同时存在时出现错误:
试过了将Ball的内容注释掉,只剩下Cylinder也可以正常运行。
经过搜索将两个子类声明前加virtual也不顶用
这是为什么啊?