void levelOrder(node * root) {
    static int i=0;
    if(i==0){
        printf("%d ",root->data);
        i++;
    }
    if(root==NULL)
        return;
    if(root->left==NULL && root->right==NULL);
        return;
    if(root->left!=NULL)
        printf("%d ",root->left->data);
    if(root->right!=NULL)
        printf("%d ",root->right->data);
    levelOrder(root->left);
    levelOrder(root->right);    
}