将带头节点单链表元素逆置 C语言

向右看齐 2022-09-09 06:08 186阅读 0赞

函数fun的功能是将带头结点的单向链表逆置。

若原链表中从头至尾结点数据域依次为：2、4、6、8、10

逆置后，从头至尾结点数据域依饮为：10、8、6、4、2

#include <stdio.h>
    #include <stdlib.h>
    #define N 5
    typedef struct node
    {
       int data;
       struct node *next;
    } NODE;
    void fun(NODE *h) {
       NODE *p, *q, *r;
       p = h->next;
       if (p == NULL)
          return;
       q = p->next;
       p->next = NULL;
       while (q) {
          r = q->next;
          q->next = p;
          p = q;
          q = r;
       }
       h->next = p;
    }
    NODE *creatlist(int a[]) {
       NODE *h, *p, *q;
       int i;
       h = (NODE *)malloc(sizeof(NODE));
       h->next = NULL;
       for (i = 0; i < N; i++) {
          q = (NODE *)malloc(sizeof(NODE));
          q->data = a[i];
          q->next = NULL;
          if (h->next == NULL)
             h->next = p = q;
          else
          {
             p->next = q;
             p = q;
          }
       }
       return h;
    }
    void outlist(NODE *h){
       NODE *p;
       p = h->next;
       if (p == NULL)
          printf("The list is NULL!\n");
       else {
          printf("\tHead");
          do {
             printf("->%d", p->data);
             p = p->next;
          } while (p != NULL);
          printf("->End\n");
       }
    }
    int main(){
       NODE *head;
       int a[N] = {2, 4, 6, 8, 10};
       head = creatlist(a);
       printf("The original list:\n");
       outlist(head);
       fun(head);
       printf("The list after inverting:\n");
       outlist(head);
    }

程序结果：

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