import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class HelloFX extends Application {

    @Override
    public void start(Stage stage) {
        stage.setTitle("Rechenprogramm");

        var grid = new GridPane();
        grid.setAlignment(Pos.CENTER);
        grid.setPadding(new Insets(5, 5, 5, 5));
        grid.setHgap(5);
        grid.setVgap(5);

        var title = new Text("Rechenprogramm");
        title.setFont(Font.font("Arial", FontWeight.BOLD, 25));
        grid.add(title, 0, 0, 4, 1);

        var numberLabel = new Label("Zahl:");
        grid.add(numberLabel, 0, 1);

        var numberInput = new TextField();
        grid.add(numberInput, 1, 1, 3, 1);

        var doubleButton = new Button("Doppelt");
        grid.add(doubleButton, 1, 3);

        var quadratButton = new Button("Quadrat");
        grid.add(quadratButton, 2, 3);

        var squareButton = new Button("Wurzel");
        grid.add(squareButton, 3, 3);

        var result = new Text();
        grid.add(result, 1, 2, 3, 1);

        doubleButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent e) {
                var value = numberInput.getText();
                var number = Integer.parseInt(value);

                result.setText(Integer.toString(number * 2));
            }
        });
        quadratButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent e) {
                var value = numberInput.getText();
                var number = Integer.parseInt(value);

                result.setText(Integer.toString(number * number));
            }
        });
        squareButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent e) {
                var value = numberInput.getText();
                var number = Integer.parseInt(value);

                result.setText(Double.toString(Math.sqrt(number)));
            }
        });

        Scene scene = new Scene(grid, 500, 300);
        stage.setScene(scene);
        stage.show();
    }

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

}