c++ 子类构造函数初始化及父类构造初始化的使用

class animal
{
protected:  //成员变量，声明为protected或者public，这里选择protected
	int height; //若声明为private，则不能被子类继承访问，会报错
	int weight;
public:
	animal(int height,int weight) //带参的构造函数
	{
		this->height=height;
		this->weight=weight;
		cout<<"animal的带参构造函数被调用"<<endl;
	}
	virtual ~animal()
	{
		cout<<"animal的析构函数被调用"<<endl;
	}
};
//子类
class fish:public animal
{
public:
	fish():animal(height,weight) //显示调用父类的构造函数
	{
		cout<<"fish的构造函数被调用"<<endl;
	}
	virtual ~fish()
	{
		cout<<"fish的析构函数被调用"<<endl;
	}
};

// 父类的构造函数，改成带有默认值的参数， 这样在子类中就可以不用显示调用了
  animal(int height=19 ,int weight=20) //带参的构造函数
  {
    this->height=height;
    this->weight=weight;
    cout<<"animal的带参构造函数被调用"<<endl;
  }

//父类
class animal
{
protected:  //成员变量，声明为protected或者public，这里选择protected
	int height; //若声明为private，则不能被子类继承访问，会报错
	int weight;
public:	
	animal()
	{
		height=0;
		weight=0;
		cout<<"animal的无参构造函数被调用"<<endl;
	}
	animal(int height,int weight) //带参的构造函数
	{
		this->height=height;
		this->weight=weight;
		cout<<"animal的带参构造函数被调用"<<endl;
	}
	virtual ~animal()
	{
		cout<<"animal的析构函数被调用"<<endl;
	}
};
//子类
class fish:public animal
{
public:
	fish()  //没有显示地调用父类的构造函数(无参或带参)，则默认调用父类的无参构造函数
	{
		cout<<"fish的构造函数被调用"<<endl;
	}
	virtual ~fish()
	{
		cout<<"fish的析构函数被调用"<<endl;
	}
};