函数题：骡子*

请设计以下食草动物、马、驴、骡等 4 个类。

- HERB 为食草动物类，是公共基类，具有食草动物的基本特性。包括：

一个保护数据成员：appet(食量)。

三个公有成员函数：构造函数(初始化食量)、析构函数和 Show 函数(显示食量)。

- HORSE 为马类，以公有方式继承 HERB 类，具有食草动物的特性，还能跑得很快。包括：

一个保护数据成员：speed(速度)。

三个公有成员函数：构造函数、析构函数和 Show 函数(显示食量和速度)。

- DONKEY 为驴类，以公有方式继承 HERB 类，具有食草动物的特性，还能驼重物。包括：

一个保护数据成员：load(负重)。

三个公有成员函数：构造函数、析构函数和 Show 函数(显示食量和负重)。

- MULE 为骡类，同时以公有方式继承 HORSE 类和 DONKEY 类，兼具马和驴的特性。包括：

三个公有成员函数：构造函数、析构函数和 Show 函数(显示食量、速度和负重)。

#### 测试用例

- 样例一

c++
HERB *p;
p = new HERB(2.1);
p->Show();
delete p;



A herb is born.
I need 2.1 kg food.
A herb is dead.


- 样例二

c++
HERB *p;
p = new HORSE(4.5, 58.2);
p->Show();
delete p;



A herb is born.
A horse is born.
I need 4.5 kg food, I can run at 58.2 km/h.
A horse is dead.
A herb is dead.


- 样例三

c++
HERB *p;
p = new DONKEY(2.4, 213.7);
p->Show();
delete p;



A herb is born.
A donkey is born.
I need 2.4 kg food, I can carry 213.7 kg load.
A donkey is dead.
A herb is dead.


- 样例四

c++
HERB *p;
p = new MULE(2.8, 46.7, 208.9);
p->Show();
delete p;



A herb is born.
A horse is born.
A donkey is born.
A mule is born.
I need 2.8 kg food, I can run at 46.7 km/h, I can carry 208.9 kg load.
A mule is dead.
A donkey is dead.
A horse is dead.
A herb is dead.


#### 裁判程序

c++
#include <iostream>
using namespace std;

/* 你提交的代码将被嵌在这里 */

int main()
{
double a, s, l;
HERB *p;
cin >> a >> s >> l;
p = new MULE(a, s, l);
p->Show();
delete p;
return 0;
}


#### 输入样例
in
2.1 54.6 198.3



#### 输出样例

out
A herb is born.
A horse is born.
A donkey is born.
A mule is born.
I need 2.1 kg food, I can run at 54.6 km/h, I can carry 198.3 kg load.
A mule is dead.
A donkey is dead.
A horse is dead.
A herb is dead.








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