added some classes for future functionality

src/hellofx/Calculator.java

+package hellofx;
+
+// import java.util.ArrayList;
+
+public class Calculator {
+    // private ArrayList<Value> values; maybe in future
+    private Value first = new Value();
+    private Value second = new Value();
+
+}
\ No newline at end of file

src/hellofx/Controller.java

@@ -37,6 +37,9 @@ public class Controller {
     @FXML
     private Button zero;
 
+    /*
+     *  the function reacts on clicked Buttons
+     */
     private void setButtons(){
         one.setOnAction(new EventHandler<ActionEvent>(){
 

src/hellofx/Main.java

@@ -7,12 +7,12 @@ import javafx.scene.Scene;
 import javafx.stage.Stage;
 
 public class Main extends Application {
-    
+
     @Override
     public void start(Stage primaryStage) throws Exception{
         Parent root = FXMLLoader.load(getClass().getResource("hellofx.fxml"));
         primaryStage.setTitle("Calculator");
-        primaryStage.setScene(new Scene(root, 400, 300));
+        primaryStage.setScene(new Scene(root, 400, 350));
         primaryStage.show();
     }
 

src/hellofx/Value.java

+package hellofx;
+
+public class Value {
+    private int selfValue = 0;
+    private int dec = 0;
+
+    // Value(int _v, int _d){
+    //     this.selfValue = _v;
+    // }
+
+
+}