逆转链表 为什么出来什么也没有

void ReverseList(Node** phead) {
    Node* p = *phead;
    if (!p->next)
        return;
    else {
        Node* prev = NULL;
        Node* cur = p;
        Node* next = p->next;
        while (cur) {
            cur->next = prev;
            prev->next = NULL;
            prev = cur;
            cur = next;
            next = next->next;
        }
    }
}

while (cur) {
            cur->next = prev;
            prev->next = NULL;  //这句不要试试
            prev = cur;
            cur = next;
            next = next->next;
        }