无头单链表反转

#include <iostream>                                                                                                 

using namespace std;

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


node *list_create(void)
{
    node *head = NULL; 
    node **current = &head;

    cout << "input value until -1" << endl;

    int a = 0;
    cin >> a;
    while(a != -1)
    {
        *current = new node;
        (*current)->next = NULL; 
        (*current)->data = a;
        current = &((*current)->next);
        cin >> a;
    }

    return head;
}

void list_print(const node *head)
{

    while(head)
    {
        cout << "node->next is : " << head->next << " node->data is : " << head->data <<endl; 
        head = head->next;
    }
}

node *node_delete(node *head, int data)
{
    if(head == NULL)
        return head;

    node *current = head;
    node *prev = head;

    if(head->data == data)
    {
        head = head->next;
        current->next = NULL;
        delete current;
        return head;
    }


    while(current)
    {
        if(current->data == data)
            break;
        prev = current;
        current = current->next;
    }

    if(current)
    {
        prev->next = current->next;
        current->next = NULL;
        delete current;
    }

    return head;
}

void list_delete(node *head)
{
    node *temp;
    while(head)
    {
        temp = head; 
        head = head->next;
        temp->next = NULL;
        delete temp;
    }
}

node* list_insert(node *head, int data)
{
    node *node_new = new node;
    node_new->data = data;
    node_new->next = NULL;

    if(head == NULL)
    {
        head = node_new;
        return head;
    }

    if(head->data >= data)
    {
        node_new->next = head;
        head = node_new;
        return head;
    }

    node *prev = head;
    node *current = head;

    while(current)
    {
        if(current->data < data)
        {
            prev = current;
            current = current->next;
            continue;
        }
        break;
    }

    node_new->next = current;
  prev->next=node_new;      
    return head;
}

node *list_rev(node *head)
{
    if(NULL == head)
        return head;

    node *prev = head;
    node *current = head;
    node *next = head->next;


    while(next != NULL)
    {
        current = next;
        next = current->next;
        current->next = prev;
        prev = current;
    }

    head->next = NULL;
    head = current;
    return head;
}

node *create_sort(void)
{
    node * head = NULL;
    int a = 0;
    cin >> a;
    while(a != -1)
    {
        head = list_insert(head, a);
        cin >> a;
    }

    return head;
}
int main(void)
{
    node *head;
    int num;
    head = list_create();
    list_print(head);

    cout << "input the delete number" << endl;
    cin >> num;

    head = node_delete(head, num);

    list_print(head);

    list_delete(head);

    head = create_sort();

    list_print(head);

    head = list_rev(head);

    list_print(head);   

    list_delete(head);

    return 0;
}