import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.util.Random;

public class RandomWalk extends Application {
    private Button button = new Button();
    private int counter = 0;
    private Label label = new Label("" + this.counter);
    private final Random random = new Random();
    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("Random Walk");
        this.button.setText((random.nextBoolean() ? "Up" : "Down"));
        BorderPane borderPane = new BorderPane();
        borderPane.setPadding(new Insets(20, 20,20,20));
        borderPane.setCenter(this.button);
        BorderPane.setAlignment(this.button, Pos.CENTER);
        borderPane.setBottom(label);
        BorderPane.setAlignment(label, Pos.BOTTOM_CENTER);
        Scene scene = new Scene(borderPane, 300, 250);
        primaryStage.setScene(scene);
        this.button.setOnAction(e -> {
                counter += (button.getText().equals("Up") ? 1 : -1);
                button.setText((random.nextBoolean() ? "Up" : "Down"));
                label.setText("" + counter);
            });
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}