Binary Search Tree

typedef struct Node {
    int data;
    struct Node* left;
    struct Node* right;
 
}Node;
 
void insertNode(Node* node, int x) {
    Node* parent;
    Node* tmp;
    Node* newNode;
 
    parent = NULL;
    tmp = node;
 
    while (tmp != NULL) {
        parent = tmp;
 
        //삽입하기 적절한 위치로 이동한다. 
        if (tmp->data > x) {
            //왼쪽자식=
            if (tmp->left != NULL) {
                tmp = tmp->left;
            }
            else break;
 
        }
        else {
            if (tmp->right != NULL) {
                tmp = tmp->right;
            }
            else {
                break;
            }
        }
    }
 
    newNode = new Node;
 
    if (parent->data > x) {
        parent->left = newNode;
    }
    else
        parent->right = newNode;
 
    newNode->data = x;
    newNode->left = NULL;
 
    newNode->right = NULL;
 
}
 
void postOrder(Node* root) {
    if (root) {
        postOrder(root->left);
        postOrder(root->right);
        cout << root->data << ' ';
    }
}
 
int main() {
    // insert code here...
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
 
    int tmp;
 
    cin >> tmp;
 
    int root_data;
    root_data = tmp;
 
    Node* root = new Node;
    root->data = root_data;
    root->left = NULL;
    root->right = NULL;
 
    while (cin>>tmp) {
        insertNode(root,tmp);
    }
 
 
    postOrder(root);
 
    return 0;
}