Question

package Week7_Quiz;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.control.Label;
import javafx.stage.Stage;

public class Week7_Quiz extends Application {
private TextField tf1;
private Label stckr;
private int revrsdNum;
private Button btn;
int num = 0;
int reverse;

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

@Override
public void start(Stage stage) throws Exception {
tf1 = new TextField();
tf1.setLayoutX(10);
tf1.setLayoutY(50);
  
stckr =new Label ("Result: ");
stckr.setLayoutX(12);
stckr.setLayoutY(100);
  
btn = new Button("Reverse");
btn.setLayoutX(10);
btn.setLayoutY(250);
btn.setOnAction(this::revrsdNum);
  
Group gp = new Group(tf1, stckr, btn);

Scene scene = new Scene(gp, 500, 650);
  
stage.setScene(scene);
stage.setTitle("Week 7 Quiz");
stage.show();
  
}

private void revrsdNum(ActionEvent t) { // need help fixing while loop
while(num != 0){
int dig = num%10;
revrsdNum = reverse*10+dig;
num/=10;
revrsdNum = revrsdNum + tf1.getText().charAt(num);

}
  
stckr.setText("Result: " + revrsdNum);

}
  
}

I am trying to solve using this while loop but its giving me error. I need help fixing while loop and run the GUI code. Please help!! thank you

Answer 1

If you have any problem with the code feel free to comment. I'm assuming that the program is to reverse a number. I have uploaded the rectified method please replace it with your own, the rest of the program remains same.

revrsdNum method

    private void revrsdNum(ActionEvent t) { // need help fixing while loop
                //num was not initialized 
                num = Integer.parseInt(tf1.getText());
                //setting the revrsdNum to 0 every time this method is called
                revrsdNum = 0;
                while (num != 0) {
                        int dig = num % 10;
                        //revrsdNum will be multiplied with 10 not reverse
                        revrsdNum = revrsdNum * 10 + dig;
                        num /= 10;
                }
                stckr.setText("Result: " + revrsdNum);
        }

Output