【数据结构课程作业】单链表就地逆置

#include <stdio.h>
#include <stdlib.h>

typedef struct List {
    int val;
    struct List *next;
}List;

void InitList(List **h, List **t)
{
    *h = (List *)malloc(sizeof(List));//*h就是头指针的地址
    *t = (List *)malloc(sizeof(List));//*t就是尾指针的地址
    if(!(*h) || !(*t)) exit(-1);
    (*h)->next = *t;
    (*t)->next = NULL;
    printf("初始化成功\n");
}

List *CreateList(List *h)
{
    int input;
    while(~scanf("%d", &input)) {
        List *p = (List *)malloc(sizeof(List));
        if(!p) exit(-1);
        p->val = input;
        p->next = h->next;
        h->next = p;
    }
    printf("创建成功\n");
    return h;
}

void PrintList(List *h)
{
    List *p = h->next;
    while(p) {
        if(p->next) printf("%d ", p->val);
        p = p->next;
    }
    printf("\n");
}

void ClearList(List *h)
{
    List *p = NULL;
    while(h) {
        p = h;
        h = h->next;
        free(p);
    }
    printf("清空完毕\n");
}

void InvertList(List *f, List *p)
{
    if(p->next) InvertList(p, p->next);
    p->next = f;
}

int main()
{
    List *head = NULL, *tail = NULL;
    InitList(&head, &tail);//传入指针的地址，这是一个二级指针
    printf("逆序输入数据，以EOF结束标志\n");
    head = CreateList(head);//输入数据创造一个带头带尾的链表
    PrintList(head);
    InvertList(NULL, head);//递归倒置
    printf("逆置成功\n");
    PrintList(tail);//尾指针变成了头指针
    ClearList(tail);
    return 0;
}