如何将顺序表改为逆序表

Question

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
typedef struct Node{ int data; int len; struct Node *pNext;}NODE,*PNODE;
PNODE creat_list(int len)//创建链表， {
int i; int val;
PNODE pHead = (PNODE)malloc(sizeof(NODE));
if (NULL == pHead){
printf("分配失败, 程序终止!\n"); exit(-1);} PNODE pTail = pHead;
pTail->pNext = NULL;
for (i=0; i<len; ++i){scanf("%d", &val); PNODE pNew = (PNODE)malloc(sizeof(NODE)); if (NULL == pNew) { printf("分配失败, 程序终止!\n"); exit(-1);} pNew->data = val;
pTail->pNext = pNew;
pNew->pNext = NULL;
pTail = pNew; }return pHead;}
void traverse_list(PNODE pHead,int len)//遍历链表{ PNODE p = pHead->pNext; int count=1; while(NULL!=p){
if(count==len) { printf("%d",p->data); } else { printf("%d ",p->data); } p = p->pNext; count++; } printf("\n"); return;}
int main(){ int len; while(~scanf("%d",&len)) { PNODE pHead=NULL;//等价于struct Node *pHead= NULL //创建链表creat_list2(); pHead=creat_list(len);//创建一个非循环单链表，并将其该链表的头结点指向PHead traverse_list(pHead,len);//遍历整个链表 free(pHead); } return 0;}

Answer 1

运行结果及代码如下：

代码：

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
typedef struct Node
{
    int data;
    int len;
    struct Node* pNext;
}NODE, * PNODE;
PNODE creat_list(int len)//创建链表， 
{
    int i; int val;
    PNODE pHead = (PNODE)malloc(sizeof(NODE));
    if (NULL == pHead) {
        printf("分配失败, 程序终止!\n"); exit(-1);
    }
    PNODE pTail = pHead;
    pTail->pNext = NULL;
    for (i = 0; i < len; ++i) 
    {
        scanf("%d", &val);
        PNODE pNew = (PNODE)malloc(sizeof(NODE));
        if (NULL == pNew) { printf("分配失败, 程序终止!\n"); exit(-1); }
        pNew->data = val;
        pTail->pNext = pNew;
        pNew->pNext = NULL;
        pTail = pNew;
    }
    return pHead;
}
void traverse_list(PNODE pHead, int len)//遍历链表
{
    PNODE p = pHead->pNext;
    int count = 1;
    while (NULL != p)
    {
        if (count == len)
        {
            printf("%d", p->data);
        }
        else
        {
            printf("%d ", p->data);
        }
        p = p->pNext;
        count++;
    }
    printf("\n");
    return;
}


//逆序
void reverse(PNODE pHead)
{
    PNODE p,  t,q;
    p = pHead->pNext;
    if (p == 0 || p->pNext == 0) return;

    t = p->pNext;
    p->pNext = 0; 

    while (t)
    {
        pHead->pNext = t;
        
        q = t->pNext;
        t->pNext = p;
        p = t;
        t = q;
    }
}


int main() {
    int len;
    while (~scanf("%d", &len))
    {
        PNODE pHead = NULL;//等价于struct Node *pHead= NULL 
        //创建链表creat_list2(); 
        pHead = creat_list(len);//创建一个非循环单链表，并将其该链表的头结点指向PHead 
        traverse_list(pHead, len);//遍历整个链表 

        //逆序
        printf("\n逆序后：");
        reverse(pHead);
        traverse_list(pHead, len);//遍历整个链表 
        free(pHead);
    }
    return 0;
}