删除链表之two star programming

时间：2014-03-10 04:51:14 阅读：388 评论：0 收藏：0 [点我收藏+]

最近偶尔看到一篇关于Linus Torvalds的访问，大神说大部分人都不理解指针。假设被要求写一段链表删除节点的程序，大多数的做法都是跟踪两个指针，当前指针cur和其父节点pre，这种实现很容易理解，但是并没有用到指针的精髓。

Linus是怎么写的呢，且看源代码

//链表之two star programming
#include <stdio.h>
 
typedef 
struct node
{
    int 
value;
    struct 
node *next;
}listNode;
 
listNode *insert(listNode *head, int 
value)
{
    listNode *newNode = new 
listNode;
    newNode->value = value;
    newNode->next = head;
    return 
newNode;
}
 
void 
erase(listNode **head_in, int 
value)
{
    listNode **cur = head_in;
    while 
(*cur)
    {
        listNode *p = *cur;
        if 
(p->value == value)
        {
            *cur = p->next;
            delete 
p;
        }
        else
        {
            cur = &(p->next);
        }
    }
    //return head;
}
 
void 
printList(listNode *head)
{
    listNode *p = head;
    while(p)
    {
        printf("%d ", p->value);
        p = p->next;
    }
    printf("\n");
}
 
int 
main()
{
    listNode *head = NULL;
    int 
select, a;
    do
    {
        printf("请输入选择 1--插入， 2--删除, 3--输出，其他跳出\n");
        scanf("%d", &select);
        if(select == 1)
        {
            printf("输入将要插入的值, -1表示结束\n");
            while(scanf("%d", &a), a != -1)
            {
                head = insert(head, a);
            }
        }
        else 
if(select == 2)
        {
            printf("输入将要删除的值, -1表示结束\n");
            while(scanf("%d", &a), a != -1)
            {
                erase(&head, a);
            }
        }
        else 
if(select == 3)
        {
            printList(head);
        }
        else 
break;
     
    } while 
(1);
 
    getchar();
    return 
0;
}