class Node {
    Node *left, Node *right;
    Void #ctor( Int depth ) { // constructor
        if( depth > 0 ) {
            left = new Node( depth - 1 );
            right = new Node( depth - 1 );
        }
    }
}

@ctime Node *a = new Node( 5 );
Node *b = new Node( 2 );

Void main() {
    const( Node ) *ptr = userInput ? a : b;
    printTree( ptr );
}