How to modify JOptionPane method in Java

Question

Please, I need your help. Whenever I tried to run the below program, it will say incompatible types, String cannot be converted to Integer.

import javax.swing.JOptionPane;

public class Addition
{
  public static void main(String[] args)
  {
     String num1 = (Integer)JOptionPane.showInputDialog("Enter num1");
     String num2 = (Integer)JOptionPane.showInputDialog("Enter num2");

     String sum =
         (Integer)String.format("The sum is: %d", (num1 + num2));

     JOptionPane.showMessageDialog(null, sum);
  }
}

Answer 1

To expound on the other answers and show the code, here is what you need to make it work:

import javax.swing.JOptionPane;

public class Addition
{
  public static void main(String[] args)
  {
     int num1 = Integer.parseInt(JOptionPane.showInputDialog("Enter num1"));
     int num2 = Integer.parseInt(JOptionPane.showInputDialog("Enter num2"));

     String sum = String.format("The sum is: %d", (num1 + num2));

     JOptionPane.showMessageDialog(null, sum);
  }
}

You want to take the input from the JOptionPanes as an int s then add them and put the result in a string , not cast a string to an int .

NOTE: I wrote this on my mobile, so I'll compile and run it when I get home, but above is the general idea.

Answer 2

Your best bet is to take an int in the first place.

int num1 = Integer.parseInt(JOptionPane ...

And you can either do the same with the output, or parse it again.

Answer 3

Its because your typecasting a String to an Integer and trying to store it in a String.

Remove (Integer) from the statement to get rid of that error.

Answer 4

Try this

    int num1 =  Integer.valueOf(JOptionPane.showInputDialog("Enter num1"));
    int num2 =  Integer.valueOf(JOptionPane.showInputDialog("Enter num2"));

     String sum = String.format("The sum is: %d", (num1 + num2));

     JOptionPane.showMessageDialog(null, sum);

Answer 5

It's seems you want, something like this:

    public static void main(String[] args) {
    Integer num1 = Integer.parseInt(JOptionPane.showInputDialog("Enter num1"));
    Integer num2 = Integer.parseInt(JOptionPane.showInputDialog("Enter num2"));

    String sum = String.format("The sum is: %d", (num1 + num2));

    JOptionPane.showMessageDialog(null, sum);
}