C++ 链表

#include <iostream>
using namespace std;

template <typename T>
struct Node
{
T t; //
struct Node<T> *next;
};

template <typename T>
class LinkList
{
public:
LinkList();
~LinkList();

public:
int clear();
int insert(T &t, int pos);
int get(int pos, T &t);
int del(int pos, T &t);
int getLen();

protected:
Node<T> *m_header;
int m_len;

};

template <typename T>
LinkList<T>::LinkList()
{
m_header = new Node<T>;
m_header->next = NULL;
m_len = 0;
}

template <typename T>
LinkList<T>::~LinkList()
{
Node<T> *tmp = NULL;

while (m_header !=NULL)//加进去的节点都是new出来的，在堆中，所以这里要手动释放，因为程序不会自动释放。
{
tmp = m_header->next;
delete m_header;
m_header = tmp;
}
}

template <typename T>
int LinkList<T>::clear()
{

//把旧的结点 del掉
Node<T> *tmp = NULL;

while (m_header)
{
tmp = m_header->next;
delete m_header;
m_header = tmp;
}

//重新创建
m_header = new Node<T>;
m_len = 0;

return 0;
}

template <typename T>
int LinkList<T>::insert(T &t, int pos)
{
Node<T> *current = NULL;

current = m_header;

for (int i=0; i<pos; i++)
{
current = current->next;
}

//把上层应用的t结点 缓存到容器中

Node<T> *node = new Node<T>;//此处会调用T也就是Teacher的无参构造函数实现拷贝，因为放到容器里面是调用了对象的构造函数实现拷贝的，因此Teacher里面要提供一个无参构造函数，如果Teacher里面提供了有参构造函数则就没有无参构造函数了，如果没有无参构造函数则此处写成new Node<T>(1,"name"),
node->next = NULL;
node->t = t; // 把t1缓存下来

//把node结点 在pos位置 加入到链表中

node->next = current->next;
current->next = node;

m_len ++;
return 0;
}

template <typename T>
int LinkList<T>::get(int pos, T &t)
{
Node<T> *current = NULL;

current = m_header;

for (int i=0; i<pos; i++)
{
current = current->next;
}
t = current->next->t;
return 0;
}

template <typename T>
int LinkList<T>::del(int pos, T &t)
{
Node<T> *current = NULL;
Node<T> *ret = NULL;

current = m_header;

for (int i=0; i<pos; i++)
{
current = current->next;
}
ret = current->next;
t = ret->t; //把缓存的结点 给上层应用t

//删除操作
current->next = ret->next;
m_len --;
delete ret; //注意释放内存  因为insert的时候 new Node<T>

return 0;
}

template <typename T>
int LinkList<T>::getLen()
{
return m_len;
}

#include <iostream>
using namespace std;

#include "LinkList.h"

struct Teacher
{
char name[32];
int age;
};

void main01()
{
Teacher t1, t2, t3;
Teacher  tmp;
t1.age = 31;
t2.age = 32;
t3.age = 33;

LinkList<Teacher> list;

//插入元素
list.insert(t1, 0);
list.insert(t2, 0);
list.insert(t3, 0);

//遍历链表

for (int i=0; i<list.getLen(); i++)
{
list.get(i, tmp);
printf("age:%d ", tmp.age);
}

//销毁链表
while (list.getLen() > 0)
{
list.del(0, tmp);
printf("age:%d ", tmp.age);
}

}

void main()
{
main01();
cout<<"hello..."<<endl;
system("pause");
return ;
}