Inifinite recursion when executing function in C - c

Question

I tried writing a tree program in C, starting with the insert function as shown below:
void insert(int val)
{
struct node * nn = (struct node *)malloc(sizeof(struct node));
nn->data = val;
nn->left = NULL;
nn->right = NULL;
if(root == NULL)
{
root = nn;
}
else
{
struct node *ptr = root;
while(ptr->left != NULL && ptr->right != NULL)
{
if(nn->data < ptr->data)
{
ptr = ptr->left;
}
else
{
ptr = ptr->right;
}
}
if(ptr->data < nn->data)
{
ptr->right = nn;
}
else
{
ptr->left = nn;
}
}
Then I wrote the code for displaying the nodes of the tree so formed:
void display()
{
struct node *n;
if(root == NULL)
{
printf("Tree is Empty\n");
}
else
{
n = root;
if(n!=NULL)
{
printf("%d",n->data);
display(n->left);
display(n->right);
}
}
}
This is the main function:
int main()
{
int ch,val;
while(ch!=3)
{
printf("1. Insert\n2. Display\n3. Exit\nEnter your choice: ");
scanf("%d",&ch);
switch(ch)
{
case 1:
printf("Enter value to be inserted: ");
scanf("%d",&val);
insert(val);
break;
case 2:
display();
break;
case 3:
ch=3;
printf("Exiting....\n");
break;
default:
printf("Invalid choice, please try again\n");
break;
}
}
return 0;
}
But when I tried executing the display function after inserting a few nodes, it only printed the first node in an infinite loop.
Could someone please help me get around this problem?

Answer 1

With each iteration (recursion) you start with root again. That will continue forever, of course.
Your function signature should be
void display(struct node *n)
and then call it in main as:
display(root);
Fixing the display function itself with this feed back I leave to you.
EDIT: the function should be:
void display(struct node *n)
{
if (n) {
printf("%d\n",n->data);
display(n->left);
display(n->right);
}
}