How to use Double selection If statements?

Question

Ok, this is what I have to do:
Present a menu to the user from which there will be 6 choices, A = add three number, S = subtract 2 numbers, M = multiply three numbers, D = divide two numbers, O = modulus two numbers, E = Exit.
2) If the user enters an A,S,M,O,D the program will prompt the user for numbers and perform the needed math on them.
3) if the user enters an E then the program will thank the user, and exit.
4)the program HAS to use Double Selection If Statements (no idea how to do these)
5) the program should use float point numbers for all the numbers entered, besides modulus.
heres what i have so far.. -_-
import javax.swing.JOptionPane;
public class Ifprogram
public static void main (String[] args)
  String Intro;
  String A;
  String S;
  String M;
  String D;
  String O;
  String Exit;
  Intro = JOptionPane.showInputDialog(null, "Enter A to add 3 numbers \n S to Subtract two numbers \n M to Multiply three numbers \n D to Divide two numbers \n O to Modulus two numbers \n and E to Exit.");
   A = JOptionPane.showInputDialog(null, "You selected to add 3 numbers. Enter the first digit to add.");
   S = JOptionPane.showInputDialog(null, "You selected to substract two numbers. Enter the first digit to subtract.");
}IM SO LOST.
If anyone could give me some tips on what to do, or where to get, that'd help A LOT! Thank you.

Answer 1

I can see that working, but
if(user entered 'A') {
                    A = JOptionPane.showInputDialog(null, "You selected to add 3 numbers. Enter the first digit to add.");
                } else if(user entered 'S') {
                   S = JOptionPane.showInputDialog(null, "You selected to substract two numbers. Enter the first digit to subtract.");
               }Is not working..
The errors i get:
16 ')' expected
               if(user entered 'A') {
                                ^
21: illegal start of expression
                ^
2 errors
Tool completed with exit code 1Edited by: JackJ11 on Mar 16, 2010 4:29 PM