【链表】1、递归删除不带头结点链表中指定值

/*
    设计一个递归算法，删除一个不带头结点的单链表中所有值为x的节点
    分析：
        首先我们要创建单链表，并赋值，然后递归去判断值，进行删除
*/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
struct Link
{
    int value;
    struct Link *next;
};
void deleteX(Link *&p, int delNum) {//这里的第一个函数参数必须是引用值，不然会导致断链
    struct Link *pre;//定义一个指针，进行删除
    if (p == NULL) return;
    if (p->value == delNum) {
        pre = p;
        p = p->next;
        free(pre);
        deleteX(p, delNum);
    }
    else
        deleteX(p->next, delNum);
}
Link *create() {
    struct Link *p, *rear, *head;
    head = (struct Link *)malloc(sizeof(struct Link));
    rear = (struct Link *)malloc(sizeof(struct Link));
    head = NULL;
    rear = NULL;
    int value;
    printf("请输入链表各节点的值，以9999结束：");
    scanf("%d", &value);
    while (value != 9999) {//依次创建节点
        p = (struct Link *)malloc(sizeof(struct Link));//创建一个新的节点
        p->value = value;
        p->next = NULL;
        if (head == NULL) {
            rear = p;
            head = p;
        }
        else {
            rear->next = p;
            rear = p;
        }
        scanf("%d", &value);
    }
    rear->next = NULL;
    return head;
}
Link *create2() {
    struct Link *p, *rear, *head;
    head = (struct Link *)malloc(sizeof(struct Link));
    head = NULL;
    int value;
    printf("请输入链表各节点的值，以9999结束：");
    scanf("%d", &value);
    while (value != 9999) {//依次创建节点
        p = (struct Link *)malloc(sizeof(struct Link));
        p->value = value;
        p->next = NULL;
        if (head == NULL) {
            head = p;
        }
        else {
            p->next = head->next;
            head->next = p;
        }
        scanf("%d", &value);
    }
    return head;
}
int main() {
    int delNum;
    struct Link *head, *q;
    head = create();
    q = head;
    printf("打印链表：");
    while (q != NULL) {
        printf("%d ", q->value);
        q = q->next;
    }
    q = head;
    printf("请输入想要删除的节点的值：");
    scanf("%d", &delNum);
    deleteX(q, delNum);
    printf("删除后链表：");
    while (q != NULL) {
        printf("%d ", q->value);
        q = q->next;
    }
    return 0;
}