Generate UserID?

[sukuiichuu]

Hello, I'm learning how to use Java and I am not really understanding what I'm doing. I am trying to create a class (which I'm having trouble understanding alone), but in this class, I'm trying to make a username that contains the first three letters of the first and last name then random numbers after it. Then just a random six digit password. This is what I have so far:

public class UserID {

private static final int MAX = 6;

private String firstName;
private String lastName;
private String user;
private String password;

public UserID (String first, String last){
firstName = first;
lastName = last;
}

public String getId()

/**
*
* @return
*/
{
return user;
}

public String setID()
{
return user;
}
public String getPassword()

{
return password;
}

public boolean setPassword(String pw) {


boolean isSet = true;
if (pw.length() >= 6) {

password = pw;
isSet = false;
}
return isSet;
}

public String generateNewPassword(int pw) {

pw = (int)(Math.random() * MAX) + 1;
return password;
}


public String toString() {
String output = "First name: " + firstName
+ " " + lastName + "\n";
output += "User ID: " + user + "\n";
output += "Password: " + password + "\n";
output += "Would you like to change your password?"
+ "(Y - Yes, N - No) ";

return output;
}

}

I'm not asking for someone to do my homework, but could someone steer me in the right direction and tell me what I'm doing wrong here?

Thank you1

[Norm]

What does the program generate now?
Show what it outputs and explain what is wrong with it.

[javapenguin]

Try using

the String method subString with parameters (0,3) to get the first three letters of the first and last names.

Either use the String method concat(String s) to put them all together or use the "+" operator to concat them together.

Create a char array with values 0-9.

char[] array = new char[10];
char[0] = '0';
char[1] = '1';
etc
char[9] = '9';

Use the Random class (in java.util package)

Random r = new Random();
String password = "";
for (int i = 0; i < 6; i++)
{
int rand = r.nextInt(10);
password = password + String.valueOf(array[rand]);
}

If the 6 digits can include letters, both capital and lowercase as well as numbers, then you'll need about


(26*2 = 52 + 10 = 62)
spots in your array.
Array will be size 62 instead of size 10.

Fill in indexes 0 through 61. (Arrays start at index 0.)

And you'll need to change the value in the nextInt() thing to 72. (It chooses random value between 0, inclusive, and the number in the brackets, exclusive.)

[sukuiichuu]

Using A as String firstName and B as String lastName in Interactions, the output is currently:
First name: A B
User ID: null
Password: null
Would you like to change your password?(Y - Yes, N - No)

Basically I am trying to figure out how to go about my User ID not null, but to make a user ID such as ab123 and how to make my Password not null, but a random six digit number.

[Norm]

Where do you assign values to the variables that you are printing and that are showing null?
user and password
If you do not give them values, they will be null.

[sukuiichuu]

Ahh, subString! Thank you javapenguin!

Also, oh derp. I guess I do need to give them values. I think I understand what I need to do now, thank you Norm!