在C中删除链表的第一个和最后一个元素

Question

struct person 
{
    int age;
    char name[100];
    struct person *next;
};

void delfirst(struct person **p)// For deleting the beginning
{
    struct person *tmp,*m;
    m = (*p);
        tmp = (*p)->next;
    free(m);
    return;

}
void delend(struct person **p)// For deleting the end
{
    struct person *tmp,*m;
    tmp=*p; 
    while(tmp->next!=NULL)
    {
        tmp=tmp->next;
    }
    m->next=tmp;
    free(tmp);
    m->next = NULL;
    return;

}

我正在寻找两个单独的函数来删除链表的第一个和最后一个元素。这是我试过的。你有什么建议？特别是首先删除对我来说是个问题。

Answer 1

    if (!p || !(*p))
       return;
    struct person *tmp;
    tmp = (*p);
    (*p) = (*p)->next;
    free(tmp);
    return;

void delend(struct person **p)// For deleting the end
{
    if (!p || !(*p))
        return;
    if (!(*p)->next)
    {
        *p = NULL;    
    }
    struct person *tmp,*m;
    tmp=*p; 
    while(tmp->next->next!=NULL)
    {
        tmp=tmp->next;
    }
    free(tmp->next);
    tmp->next = NULL;
    return;

}