Core dump with linked list

I'm writing a program that randomly creates a list of integers using a node class then splits the list at a certain value and sorts the resulting two lists then outputs them. right now I get no syntax errors, but I keep getting a segmentation fault. I bolded the statement I get a seg fault at.

Code:

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NODE.H
----------
//node class that holds int data and has accessor functions and a
//constructor

#include <cstdlib> //for NULL

class node
{
  public:
    node(int the_data = int(), node* link_field = NULL)
    {data = the_data; link = link_field;}
    void set_link(node* link_field) {link = link_field;}
    void set_data(int value) {data = value;}
    int get_data() {return data;}
    const int get_data() const {return data;}
    node* get_link() {return link;}
    const node* get_link() const {return link;}
  private:
    int data;
    node* link;
};

void head_insert (node*& head, node*& n1);
void sort_list (node*& head);
node* split_list(const int& value, node*& head);

NODE.CC
-----------
#include <cstdlib>
#include "node.h"

using namespace std;

void head_insert(node*& head, node*& n1)
{
  n1->set_link(head);
  head = n1;
}

node* split_list(const int& value, node*& head)
{
  node* head1, *head2, *temp;

  while (head != NULL)
  {
    temp = head;
    if (temp->get_data() < value)
    {
      head = head->get_link();
      head_insert(head2, temp);
    }else if (temp->get_data() >= value)
    {
      head = head->get_link();
      head_insert(head1, temp);
    }
  }
  head = head1;
  return head2;
}

void sort_list(node*& head)
{
  int temp;

  for (node* ptr = head; ptr != NULL; ptr = ptr->get_link())
  {
    for (node* cursor = ptr; cursor != NULL; cursor = cursor->get_link())
    {
      if (cursor->get_data() > ptr->get_data())
      {
        temp = ptr->get_data();
        ptr->set_data(cursor->get_data());
        cursor->set_data(temp);
      }
    }
  }
}

MAIN.CC
-----------
#include <iostream>
#include <cstdlib>
#include "node.h"

using namespace std;

int main()
{
  node* n1, *head, *head1, *temp;
  int value;

  srand(time(NULL));

  cout << "Please enter a value to split the list at: \n";
  cin >> value;
 
  n1 = new node;
  n1->set_data(rand()%25+1);
  head = n1;

  for (int i = 0; i < 10; i++)
  {
    n1->set_link(new node);
    n1 = n1->get_link();
    n1->set_data(rand()%25+1);
  }
  temp = head;
  //right here is where I get a segmentation fault. if I put a cout
  //statement inside the loop it prints the values though....it's
  //weird
  while (temp != NULL)
  {
    cout << temp->get_data();
    temp = temp->get_link();
  }
  head1 = split_list(value, head);
  sort_list(head1);
  sort_list(head);
  temp = head;
  cout << "Numbers over the split: ";
  while (temp != NULL)
  {
    cout << temp->get_data();
    temp = temp->get_link();
  }
  temp = head1;
  cout << endl << "Numbers under the split: ";
  while (temp != NULL)
  {
    cout << temp->get_data();
    temp = temp->get_link();
  }
  return 0;
}

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please help

> for (int i = 0; i < 10; i++)
> {
> n1->set_link(new node);
> n1 = n1->get_link();
> n1->set_data(rand()%25+1);
> }
You need to end the list here, by setting the last link to NULL.

Code:

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  for (int i = 0; i < 10; i++)
  {
    n1->set_link(new node);
    n1 = n1->get_link();
    n1->set_data(rand()%25+1);
  }
  n1->set_link(NULL);

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