【1】C++实现内核链表功能

内核链表：

特点：节点的指针域指向下一个节点/上一个节点的指针域，由此可以统一指针的类型，具有一般通用性，使用指针域跟数据入口地址【设为0地址】的offset来寻找数据入口，从而输出节点数据；内核链表一般为双向循环链表。

C++实现内核链表功能的例子，由此此处是参考C语言编写而成的，其中形参所用的为指针形参而不是引用，后期有时间再来修改

/*******************************************************************Author:OJ_GDUTFunction:imitate the linked list of kernelDate:2016-03-27********************************************************************/#include <iostream>#include <typeinfo>using namespace std;/* *define the pointer field */struct list_head{list_head *prev;list_head *next;};list_head head_list;//define the linked list head,此处不能声明为指针，因为如果声明为指针则并没有为struct list_head分配栈空间/* *test parameters */#if 1class score{friend int main(void);private:int num;int english;int math;public:list_head list;}stu1, stu2, stu3;#elsestruct score{int num;int english;int math;list_head list;}stu1, stu2, stu3;#endiflist_head *pos;//define the loop cursor,此处可以声明为指针，因为之后会对其进行替换 score *tmp;//define the a pointer that points to score,此处可以声明为指针，因为之后会对其进行替换 /*****************************************************Function name: INIT_LIST_HEADFunction:init the linked list head Parameters:struct list_head *list:the list_head that will be init*******************************************************/static inline void  INIT_LIST_HEAD(list_head *list){list->next = list;list->prev = list;//如果不对head_list进行初始化，此处的list->next/prev会无定义，从而出现访问冲突}/*****************************************************Function name: list_add_tailFunction:add the list from the tailParameters:list_head *l_new: the new nodelist_head *head:the list head*******************************************************/void list_add_tail(list_head *l_new, list_head *head){list_head *prev = head->prev;list_head *next = head;prev->next = l_new;next->prev = l_new;l_new->prev = prev;l_new->next = next;}/*****************************************************Function name: list_for_eachFunction:add the list from the tailParameters:list_head *pos:the &struct list_head to use as a loop cursorlist_head *head:the head for your list*******************************************************/#define list_for_each(pos, head) for(pos = head->next; pos != head; pos = pos->next)/*****************************************************Function name: list_delFunction:deletes entry from listParameters:list_head *entry：the element to delete from the list*******************************************************/static inline void list_del(list_head *entry){list_head *prev = entry->prev;list_head *next = entry->next;next->prev = prev;prev->next = next;entry->prev = nullptr;entry->next = nullptr;}/*****************************************************Function name: mainFunction:test the linked_list Parameters:void*******************************************************/int main(void){/*1.初始化表头*/INIT_LIST_HEAD(&head_list);/*2.定义节点并插入节点*/stu1.num = 1;stu1.english = 91;stu1.math = 81;list_add_tail(&(stu1.list), &head_list);stu2.num = 2;stu2.english = 92;stu2.math = 82;list_add_tail(&(stu2.list), &head_list);stu3.num = 3;stu3.english = 93;stu3.math = 83;list_add_tail(&(stu3.list), &head_list);/*3.遍历节点并取出节点*//* * 基本思路：通过decltype获取数据类型，并定义一个位于0地址的该数据， * 通过计算指针域到0地址处的差值，可以得到数据入口与指针 * 域的差值，从而可以通过指针域-差值的方式来读取节点中的 *     数据，从而达到通用双向循环链表的作用，此处是精华。 */list_for_each(pos, (&head_list)){decltype(tmp) test = 0;unsigned i = (unsigned)(&(test->list)) - (unsigned)test;tmp = (decltype(tmp))((unsigned)pos - i);cout << "No." << tmp->num << " " << "english is " << tmp->english << "，" << "math is " << tmp->math << endl;}/*4.删除节点*/list_del(&(stu1.list));list_del(&(stu2.list));list_del(&(stu3.list));/*5.再次取出节点，检验节点是否删除*/list_for_each(pos, (&head_list)){decltype(tmp) test;unsigned i = (unsigned)(&(test->list)) - (unsigned)test;tmp = (decltype(tmp))((unsigned)pos - i);cout << "No." << tmp->num << " english is " << tmp->english << ",math is " << tmp->math << endl;}system("pause");return  0;}//#define l_offsetof(TYPE, MEMBER) ((size_t)&((TYPE*)0)->MEMBER)//#define container_of(ptr, type, member) ({const typeid(((type *)0)->member)*_mptr = (ptr); (type*)((char*)_mptr-l_offsetof(type,member));})/*****************************************************Function name: list_entryFunction:get the data of listParameters:list_head *prt: the &struct list_head pointertype:the type of the struct this embeded inmember:the name of the list_struct within the struct *******************************************************///#define list_entry(ptr, type, member)  ({type *test; unsigned i = test - &(test->member); ptr - i;})

遇到的问题：

1.

   此处的使用到了强制转换，能不能想办法去掉强制转换，暂时还没想到办法，之后想到了再来解决。