Thread: Not sure what to do next (Basic java program)

You have to create a phone number generator for a cell phone company. The program should present a menu with the options to generate a phone number for Harrisburg, Carlisle, York or Lancaster. Use the random number generator to produce the last four numbers of the phone number. Upon successful generation of the cell phone number, the user should be given the option to generate another cell phone number.

The first three numbers of the phone number should be as follows:
Carlisle – 551
Harrisburg – 552
York – 553
Lancaster – 554


Heres an example of what it should look like

http://i53.tinypic.com/24b7p7b.jpg

http://i55.tinypic.com/2qltwe0.jpg


Sorry i'm really new at this so bare with me.. this is what i have so far

import java.util.*;
import javax.swing.JOptionPane;
import java.io.*;
import java.util.Random.*;
 
public class PhoneNumberGenerator
{
private String cityName;
private int carlisleNumber;
private int harrisburgNumber;
private int yorkNumber;
private int lancasterNumber;
 
public void getCity()
{
String cityName = JOptionPane.showInputDialog("Enter\r\n" +
"1 - Carlisle\r\n" +
"2 - York\r\n" +
"3 - Harrisburg\r\n" +
"4 - Lancaster\r\n");
}
 
 
public static void main(String[] args)
{
PhoneNumberGenerator x = new PhoneNumberGenerator();
 
x.getCity();
 
 
 
}
 
}

The bottom is basically the object oriented style the prof wants done... so when i compile this a dialog box comes up and its exactly like picture 1.. now where do i go from here exactly? Like when the dialog box comes up and they put 1 in it how do i make it so the number generated for Carlisle is 551 - **** (whatever the random number is). Thanks for the help.

Ok, so if you are wanting to get a random phone number, and we have the area code, you need to get 7 random numbers to start off with. The easiest way to do this, in my mind, would be to modify this statement to run 7 times (I wont do everything for you, but I will help you get there):

//Having the number as a String will allow us to Concatenate Numbers
String number = "";
 
//Make your loop here to run the next few statements 7 times. I will break them up for you to understand better
 
//Get Random Number between 0 and 9 Inclusively
int num = (int)(Math.random()*9);
//Concatinate that number to the end of our Phone Number String
number += num;

Now that we have the Phone Number, we need to attach the Area Code. You said this was your criteria:

Carlisle – 551
Harrisburg – 552
York – 553
Lancaster – 554

So we can do a bunch of IF statements or a SWITCH statement. We know we will get a number back from the User Input, where:
1 = Carlisle
2 = York
3 = Harrisburg
4 = Lancaster

So, for this, I will do a SWITCH statement. Remember that you need to get the int associated with each input before proceeding.

//Input from User
int userSelection = //Whatever the value is what was inputted from the user
//Switch Statement
switch(userSelection){
//When userSelection == 1
case 1: number = 551+number;break;
//When userSelection == 2
case 2: number = 553+number;break;
//When userSelection == 3
case 3: number = 552+number;break;
//When userSelection == 4
case 4: number = 554+number;break;
//Incase of Invalid User Input
default: //You need to decide how to handle this
}

Tell me if that helps at all.

Thanks! that does help.. and sorry for the very stupid question. I'm very new at this and i understand where to put the second part of the code (the switch statements) but where do i exactly put the first part of the code? Like I don't get the String number = ""; part.. is that part of the global variable?