How to merge two java files with InputDialog to select?Please help me!?

Question

//Addition Java application
import javax.swing.JOptionPane; // import the class
public class Addition {
// main method
public static void main(String[] args)
String firstNumber, secondNumber;
int number1, number2, sum;
// read the first number
firstNumber = JOptionPane.showInputDialog("Please enter a integer: ");
// read the second number
secondNumber = JOptionPane.showInputDialog("Please enter another integer: ");
// data type conversion
number1 = Integer.parseInt(firstNumber);
number2 = Integer.parseInt(secondNumber);
sum = number1 + number2;
// display the result
JOptionPane.showMessageDialog(null, "The sum is " + sum + ".", "Results", JOptionPane.PLAIN_MESSAGE);
System.exit(0);
//Multiplication Java Application
import javax.swing.JOptionPane;
public class Multiplication5
public static void main(String args[])
int number1, number2, number3, number4, number5, product;
String firstNumber, secondNumber, thirdNumber, forthNumber, fifthNumber ;
firstNumber =
JOptionPane.showInputDialog("Please input an integer");
secondNumber =
JOptionPane.showInputDialog("Please input another integer");
thirdNumber =
JOptionPane.showInputDialog("Please input the third integer");
forthNumber =
JOptionPane.showInputDialog("Please input the forth integer");
fifthNumber =
JOptionPane.showInputDialog("Please input the fifth integer");
number1 = Integer.parseInt(firstNumber);
number2 = Integer.parseInt(secondNumber);
number3 = Integer.parseInt(thirdNumber);
number4 = Integer.parseInt(forthNumber);
number5 = Integer.parseInt(fifthNumber);
product = number1 * number2 * number3 * number4 * number5;
JOptionPane.showMessageDialog(null, "The product is " + product, "Results", JOptionPane.PLAIN_MESSAGE);
System.exit(0);
I seek for help to merge above two java application files.
I need to call JoptionPane.showInputDialog to prompt the user to input the operation, 1 for addition, 2 for multiplication. In this dialog, the user is expected to enter the integer of 1 or 2 for the calculation.
Please help me ! Thank you!

Answer 1

Hi CRay,
You just need to call the main methods of the 2 classes according to "1" or "2" entered.
It is better if the "multiplication" and "addition" are declared as methods rather than in main methods.
Example:-
public static void Addition()
Then call
Addition.addition();
than
Addition.main(new String[]{});
as shown below.
import javax.swing.JOptionPane; // import the class
public class Test{
    public static void main(String[] args){
        // read which  operation to perform
        String operation = JOptionPane.showInputDialog("Please enter which operation : ");
        if(operation.equals("1")){
            Addition.main(new String[]{});
        else{
            Multiplication5.main(new String[]{});
}Rose