选择专项变式 2：从链表上摘掉一个结点

#include <stdio.h>

struct Node
{
    int data;
    struct Node *next;
};

int main(void)
{
    struct Node a = {1, NULL}, b = {2, NULL}, c = {3, NULL};
    struct Node *p;
    a.next = &b;
    b.next = &c;
    a.next = 【0】;          /* 把 b 从链表上摘掉 */
    for (p = &a; p != NULL; p = p->next)
        printf("%d ", p->data);
    printf("\n");
    return 0;
}

链表原来是 1 → 2 → 3。要摘掉结点 b，【0】处应填；摘掉后遍历输出【1】。