demo002.链表操作

链表逆序：

https://blog.csdn.net/ljyljyok/article/details/77996029

//链表操作:该示例中，链表头节点不存储数据
//1.链表创建
//2.链表遍历，打印
//3.链表节点长度统计
//4.链表删除
//5.插入节点
//6.删除节点
//7.拼接链表
//8.倒序
//9.排序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//declaration of node
//一个链表节点定义Node，链表节点指针定义PNode
typedef struct node
{
    int value;
    struct node* pNext;
}Node,*PNode;
//operations of list
PNode list_creat(void);
void list_free(PNode pHead);
void list_display(PNode    pHead);
int list_len(PNode pHead);
void list_delete(PNode pHead, int num);
void list_insert(PNode pHead, int num);
PNode list_splice(PNode pHead1, PNode pHead2);
void list_reverse(PNode pHead);
void list_sort_bubble(PNode pHead);

int main()
{
    int n=0;
    PNode p = list_creat();
    list_display(p);
    
    list_sort_bubble(p);
    printf("sorted:
");
    list_display(p);
    //n = list_len(p);
    //printf("len of list p=%d
",n);
    //list_insert( p,  3); list_display(p);
    //list_delete( p,  2); list_display(p);
    /*PNode p2 = list_creat();
    list_display(p2);
    p=list_splice(p, p2);
    list_display(p);*/
    //list_reverse(p); list_display(p);
    list_free(p);
    return 0;
}
//1.根据输入创建链表
PNode list_creat(void)
{
    int i;
    int len;
    int value;
    PNode pHead =(PNode)malloc(sizeof(Node));
    pHead->pNext = NULL;
    PNode pTail = pHead;
    printf("Please input nums of nodes:
");
    scanf_s("%d",&len);
    for (i = 0; i < len; i++)
    {
        PNode pNew = (PNode)malloc(sizeof(Node));
        printf("Please input value of the current node:
");
        scanf_s("%d", &value);
        pNew->value = value;
        pTail->pNext = pNew;
        pNew->pNext = NULL;
        pTail = pNew;
    }
    return pHead;
}
//删除链表
void list_free(PNode pHead)
{
    PNode p = pHead;
    PNode pb = NULL;
    while (p!= NULL)
    {
        pb = p->pNext;
        free(p);
        p = pb;
    }
    printf("current list deleted!!!
");
}
//打印链表
void list_display(PNode    pHead)
{
    PNode p = pHead->pNext;
    printf("list display:
");
    while (p != NULL)
    {
        printf("%d
", p->value);
        p = p->pNext;
    }
}
//遍历，统计长度
int list_len(PNode pHead)
{
    int len = 0;
    PNode p = pHead->pNext;
    while (p != NULL)
    {
        p = p->pNext;
        len++;
    }
    return len;
}

//指定位置插入节点
void list_insert(PNode pHead,int num)
{
    PNode p = pHead->pNext;
    int i = 1;int value;
    while (i != num )
    {
        p = p->pNext;
        i++;
    }//i==num
    PNode pNew = (PNode)malloc(sizeof(Node));
    printf("Please input value of the current node:
");
    scanf_s("%d", &value);
    pNew->value = value;
    pNew->pNext = p->pNext;
    p->pNext = pNew;
}
//指定位置删除节点
void list_delete(PNode pHead,int num)
{
    PNode p = pHead->pNext;
    PNode pb = NULL;
    int i = 1;
    while (i != (num - 1))
    {
        p = p->pNext;
        i++;
    }//i==num-1
    pb = p->pNext->pNext;
    free(p->pNext);
    p->pNext = pb;
}
//拼接链表
PNode list_splice(PNode pHead1, PNode pHead2)
{
    PNode p = pHead1->pNext;
    while (p->pNext != NULL)
    {
        p = p->pNext;
    }
    p->pNext = pHead2->pNext;
    free(pHead2);
    return pHead1;
}
void list_reverse(PNode pHead)
{
    PNode p=pHead->pNext;//指向第一个节点
    PNode pa=NULL;
    PNode pb;
    while (p != NULL)
    {
        pb = p->pNext;
        p->pNext = pa;
        pa = p;
        p = pb;
        //执行一次循环后，反转一个节点，并把指针pa，p，pb向后移动一个节点
        //执行一次后，至此，p=pb同时指向下一个待反转节点
    }
    pHead->pNext = pa;
}
//排序
void list_sort_bubble(PNode pHead)
{
    int i, j;
    PNode pa = pHead;
    PNode p = pHead->pNext;
    PNode pb; 
    PNode pc;
    PNode pend;
    pend = NULL;//pend 初始值指向链表尾节点
    p = pHead->pNext;
    while (pend!=pHead->pNext)
    {
        pa = pHead;
        p = pHead->pNext;
        while (p->pNext != pend)
        {
            pb = p->pNext;//更新pb（待比较节点）
            pc = pb->pNext;//更新pc    
            if (p->value > pb->value)
            {
                pa->pNext = pb;
                pb->pNext = p;
                p->pNext = pc;//swap 
                pa = pb;//更新pa
            }
            else
            {
                pa = p;
                p = p->pNext;    
            }
        }
        pend = p;//排序终结点前移一个节点
    }
}