Question

I am supposed to convert a program i already made into a Java console application that uses the Scanner class to read the user's input. This is the code i have that i need to convert. I don't know where to start. Here is the code

import javax.swing.JOptionPane;
public class HW3 {





public static void main (String args[])
{

String firstNum;
String secondNum;
int num1;
int num2;
int sum;
int difference;
int quotient;
int product;


firstNum = JOptionPane.showInputDialog("Enter first integer: " );
secondNum = JOptionPane.showInputDialog("Enter second integer: " );
num1 = Integer.parseInt( firstNum );
num2 = Integer.parseInt( secondNum );
sum = num1 + num2;
difference = num1 - num2;
product = num1 * num2;
quotient = num1 / num2;


JOptionPane.showMessageDialog(null, "The sum is " + sum,
"Results", JOptionPane.PLAIN_MESSAGE );
JOptionPane.showMessageDialog(null, "The difference is " + difference);
JOptionPane.showMessageDialog(null, " The quotient is" + quotient);
JOptionPane.showMessageDialog(null, "The product is" + product);
System.exit( 0 );
}
}

Answer 1

The Scanner method for reading in an int is nextInt().

You need to instantiate a Scanner, and replace the inputs and outputs.

Instead of

firstNum = JOptionPane.showInputDialog("Enter first integer: " );
secondNum = JOptionPane.showInputDialog("Enter second integer: " );

using a Scanner, you will have

// instantiate scanner
Scanner kb = new Scanner(System.in);
// output dialog
out.print("Enter first integer: ");
// input int
firstNum = kb.nextInt();
// second int
out.print("Enter second integer: ");
secondNum = kb.nextInt();

Now you need to change your output.

Instead of

JOptionPane.showMessageDialog(null, "The sum is " + sum,

include simple printlines.

System.out.println("The sum is "+sum);

And do the same for the rest of the output.