C Program to Counting total number of nodes in a tree

C Program to Counting total number of nodes in a tree

#include
#include
struct tree_node
{
 int data;
 struct tree_node *left,*right,*parent;
};
typedef struct tree_node node;
node * new_node(int x);
node * insert_node(node *root, int x);
int count_nodes(node *root);

int main()
{
 node *root=NULL;
 int i,x,max;
 printf("how many numbers do you want to enter in tree?\n");
 scanf("%d",&max);
 printf("Enter %d numbers \n",max);
 for(i=0;i<max;i++)
 {
  scanf("%d",&x);
  root = insert_node(root, x);
 }
 printf("all numbers inserted into the tree\t press enter to count");
 fflush(stdin);
 getchar();
 printf("\nThere are total %d nodes in this tree\n",count_nodes(root));
    return 0;
}

node * insert_node(node *root, int x)
{
 if(!root)
 {
  root = new_node(x);
  return root;
 }
 if(root->data > x)
  root->left = insert_node(root->left,x);
 else
  root->right = insert_node(root->right,x);
 return root;
}

int count_nodes(node *root)
{
 if(!root)
 return 0;
 else
 return(count_nodes(root->left) + 1 + count_nodes(root->right));
}

node * new_node(int x)
{
 node *furnished;
 furnished = (node*)malloc(sizeof(node));
 furnished->data=x;
 furnished->left=NULL;
 furnished->right=NULL;
 furnished->parent=NULL;
 return furnished;
}