Anyone can explain this?

[kazumahits]

import javax.swing.JOptionPane;
public class jop {

    public static void main(String[] args) {

    String i1 =
        JOptionPane.showInputDialog( "Enter first Number" );
    String i2 =
        JOptionPane.showInputDialog( "Enter second Number" );
    String i3 =
        JOptionPane.showInputDialog( "Menu \n1:Addition\n2:Subtraction\n3:Multiplication\n4:Division" );

    int n1 = Integer.parseInt( i1 );
    int n2 = Integer.parseInt( i2 );
    int n3 = Integer.parseInt( i3 );

    int a1 = n1 + n2;
    int a2 = n1 - n2;
    int a3 = n1 * n2;
    int a4 = n1 / n2;

    if (n3 == 1) {
        JOptionPane.showMessageDialog( null, "The sum is " + a1,
"Sum of Two Integers", JOptionPane.PLAIN_MESSAGE );
    }
    else if (n3 == 2) {
        JOptionPane.showMessageDialog( null, "The difference is " + a2,
"Difference of Two Integers", JOptionPane.PLAIN_MESSAGE );
    }
    else if (n3 == 3) {
        JOptionPane.showMessageDialog( null, "The Product is " + a3,
"Product of Two Integers", JOptionPane.PLAIN_MESSAGE );
    }
    else if (n3 == 4) {
        JOptionPane.showMessageDialog( null, "The Quotient is " + a4,
"Quotient of Two Integers", JOptionPane.PLAIN_MESSAGE );


    } else {
JOptionPane.showMessageDialog(null, "Please Enter a Valid Number");
}

    }
}

i cant explain this... please help me...

[sunde887]

This has got to be a homework dump, this program is so simple to understand. Try compiling and running it, see if that helps you explain it.