2次输入后没有迭代的排序链表问题

如何解决2次输入后没有迭代的排序链表问题

我的排序列表的代码是这样的：

#include<iostream>
using namespace std;
class node
{
    int data;
    node *next;
    public:
    node *head = NULL;
    
    
void *newnode(int new_data) 
{ 
    node* new_node = new node(); 
    new_node -> data = new_data; 
    new_node -> next = NULL; 
        
        if(head==NULL)
            head = new_node;
        else
        {   
                
            node *prev = NULL;
            node *current = head;
           
        while (current->next != NULL  
        && new_node -> data > current->data) { 
            prev = current;
            current = current->next; 
        } 
        new_node->next = current; 
        prev->next = new_node;
           
    }
}

    void printList() 
{ 
    node *temp = head; 
    while (temp != NULL) { 
        cout << temp->data << " "; 
        temp = temp->next; 
    } 
} 
};




int main(){
    node *n1 = new node();
    int val;
    int choice ;
    do{
        cout<< "Choice";
        cout<< "1. Enter Data" << endl <<  "2. display Sorted List" << endl << "3. Exit";
        cin >> choice;
        switch(choice){
            case 1:
                cout<< "Enter The Data You Want To Insert";
                cin >> val;
                n1->newnode(val);
                break;
            case 2:
                n1->printList();
                break;
            case 3: 
                exit(0);
                    }
    } while (choice!=3);    
    }

输出仅提供两次添加数据的选项，然后自动退出。有人可以指出我的问题吗？ 输出：

Choice1. Enter Data
2. display Sorted List
3. Exit1
Enter The Data You Want To Insert4
Choice1. Enter Data
2. display Sorted List
3. Exit1
Enter The Data You Want To Insert6

---

11.48秒后退出，返回值3221225477 按任意键继续 。 。