C++ 特性_5_继承
作者:互联网
目录
1 博客内容
之前看C++特性,不知所然,今天得空回顾以下,似有所或。
2 代码_继承
子类可以自动继承父类方法(public)和属性(private),包括构造函数(无参数的构造函数)。父类中private更改为protected,主函数不能访问,但是派生类能访问。
#include <iostream>
using namespace std;
class Box
{
public:
double get_volume(void);
void set(double l, double b, double h);
Box(); //无参数的构造函数
Box(double a, double b, double c); //可以更改变量的构造函数,重构函数
protected:
double length; // 长度
double breadth; // 宽度
double height; // 高度
};
Box::Box()
{
length = 0.0;
breadth = 0.0;
height = 0.0;
}
double Box::get_volume(void)
{
return length * breadth * height;
}
void Box::set(double len, double bre, double hei)
{
length = len;
breadth = bre;
height = hei;
}
///Box_wood(木箱子类)来自box类公有(方法)派生
// class Box_wood: public Box{
// }
class Box_wood : public Box
{
public:
Box_wood();
Box_wood(double l, double w, double h, string m);
double Box_wood_get_weight();
void Box_wood_set(double len, double wit, double hei, string mat);
private:
/* data */
string materia;
};
Box_wood::Box_wood()
{
Box();
materia = "wood";
}
Box_wood::Box_wood(double l, double w, double h, string m) //有写法,加上:Box(double l,double h)
{
//这里不能定义 height =h; //子类能继承,但是不能使用构造函数修改父类已经构造的属性???
//构造即为初始化,对父类属性初始化,2次没有必要
length = l;
height = h;
height = h;
materia = m;
}
void Box_wood::Box_wood_set(double len, double wit, double hei, string mat)
{
set(len, wit, hei);
materia = mat;
}
double Box_wood::Box_wood_get_weight()
{
double density(0.0);
double volume(0.0);
if (materia == "wood")
{
/* code */
density = 0.9;
}
else
{
density = 0;
}
volume = get_volume();
return density * volume;
}
int main()
{
Box father_box;
cout << "结果输入如下:" << endl;
cout << "father_box的构造体积" << father_box.get_volume() << endl;
father_box.set(1.1, 1.2, 3.2);
cout << "father_box的设置体积" << father_box.get_volume() << endl;
Box_wood a;
cout << "子类a的构造体积" << a.get_volume() << endl;
double weight_1(0.0);
a.Box_wood_set(4.0, 5.0, 5.0, "wood");
// a.set(16.0, 8.0, 12.0);
//不能cout箱子的长宽高,即私有成员变量在main函数中看不到.
weight_1 = a.Box_wood_get_weight();
cout << "a 的重量:" << weight_1 << endl;
return 0;
}
标签:Box,继承,double,void,特性,height,volume,wood,C++ 来源: https://blog.csdn.net/weixin_44808082/article/details/120818204