Linked list sorted insert first time try - visual-c++

Question

I am trying to code a c++ program for sorted insert of a linked list. I have given the code below. The problem is when doing my second insert i.e., insert(&head, 45); the head value is becoming 0 inside insert() function. I could not insert my second element and getting errors. Can anyone please help.
#include "stdafx.h"
#include <conio.h>
#include <iostream>
using namespace std;
struct node
{
int data;
node *next;
};
void insert (node** head, int key)
{
if(*head == NULL)
{
cout <<"List is empty, Inserting at first posistion"<<endl;
*head = new node;
(*head)->data = key;
(*head)->data = NULL;
}
else
{
struct node* temp;
temp = new node;
temp = *head;
if(key < temp->data)
{
cout<<"Key is smaller than first element. Inserting at first and moving"<<endl;
struct node* ctemp = new node;
ctemp->data = key;
ctemp->next = (*head);
//delete(ctemp);
return;
}
while(temp->next != NULL)
{
if(key > temp->data)
{
temp = temp->next;
}else
{
cout<<"Inserting the data at middle"<<temp->data<<" here"<<endl;
struct node* temp1 = new node;
temp1->data = key;
temp1->next = temp->next;
temp->next = temp1;
delete(temp1);
return;
}
}
if(key > temp->data)
{
cout<<"Inserting at last"<<endl;
struct node* last = new node;
last->data = key;
last->next = NULL;
temp->next = last;
delete(last);
return;
}
}
}
void print(struct node *head)
{
struct node* temp = head;
cout<<"Element in the list"<<endl;
while(temp != NULL)
{
cout<<temp->data<<"->";
temp = temp->next;
}
delete(temp);
}
int main()
{
struct node* head = NULL;
insert(&head, 21);
insert(&head, 45);
insert(&head, 5);
print(head);
getch();
delete(head);
return 0;
}

Answer 1

Change (*head)->data = NULL; to (*head)->next = NULL; if the list is empty.