C++类的组合

1.以另一个类的对象为数据成员，必须采用初始化参数列表的写法

#include 
#include 
using namespace std;
class Boy
{
public:
	Boy(string name, int age) :name(name), age(age){}
	void printBoy()
	{
		cout << name << "t" << age << endl;
	}
protected:
	string name;
	int age;
};
class Girl
{
public:
	Girl(string boyname, int boyage, string name) :boy(boyname, boyage), name(name){}
	void printGirl()
	{
		boy.printBoy();
		cout << name << endl;
	}
protected:
	string name;
	Boy boy;
};
int main()
{
	Girl mm("男孩", 21, "女孩");
	mm.printGirl();
	return 0;
}

2.类的组合构造顺序（和定义对象顺序有关）

3.类中类（链表遍历）

#include 
#include 
using namespace std;
struct Node
{
	int data;
	Node* next;
	Node()//头
	{
		this->next = nullptr;
	}
	Node(int data)//插入
	{
		this->next = nullptr;
		this->data = data;
	}
};
class List
{
public:
	List()
	{
		headNode = new Node;
	}
	void push_front(int data)
	{
		Node* newNode = new Node(data);
		newNode->next = headNode->next;
		headNode->next = newNode;
	}
protected:
	Node* headNode;
public:
	//迭代器-->类模仿指针行为
	class iterator//遍历
	{
	public:
		iterator(Node* pMove = nullptr) :pMove(pMove) {}
		void operator=(Node* pMove)
		{
			this->pMove = pMove;
		}
		bool operator!=(Node* pMove)//重载!=
		{
			return this->pMove != pMove;
		}
		iterator operator++()//重载前置++
		{
			pMove = pMove->next;
			return iterator(pMove);
		}
		Node*& operator*()//重载*
		{
			return pMove;
		}
	protected:
		Node* pMove;
	};
	Node* begin()//头节点的next
	{
		return headNode->next;
	}
	Node* end()//尾节点的空
	{
		return nullptr;
	}
};
//类中枚举类型
class  A
{
public:
	enum time { first, second };
protected:
	enum date { mon, sur, tus };
	//类中的枚举类型受权限限定
};
int main()
{
	List list;
	for (int i = 0; i < 3; i++)
	{
		list.push_front(i);
	}
	List::iterator iter;
	for (iter = list.begin(); iter != list.end(); ++iter)
	{
		cout << (*iter)->data;
	}
	//cout << A::date::mon << endl; 受权限限定，不可访问
	cout << A::time::first << endl;
	return 0;
}