Question

Write a class called CheckUserName.

CheckUserName must have a main method.

Your program must ask for a user name.  If the name is on the list
below (Liam, for example) greet the user saying:

welcome back: Liam

If the user is an admin (like Benkamin, for example) print:

welcome back: Benjamin
you have admin privileges

Your program must accept upper case or lower case:

emacs% java CheckUserName
enter a user name: Liam
welcome back: Liam
emacs% java CheckUserName
enter a user name: liam
welcome back: liam


Here is the list of users:

Liam
Noah
William
James
Oliver
Benjamin admin
Elijah
Lucas
Mason
Logan
Alexander admin
Ethan
Jacob
Michael
Daniel admin
Henry
Jackson
Sebastian

Don't use switch

Examples:

emacs% java CheckUserName
enter a user name: Liam 
welcome back: Liam 
emacs% java CheckUserName 
enter a user name: liam 
welcome back: liam 
emacs% java CheckUserName 
enter a user name: Oliver 
welcome back: Oliver 
emacs% java CheckUserName 
enter a user name: Benjamin 
welcome back: Benjamin 
you have admin privileges 
emacs% java CheckUserName 
enter a user name: benjamin 
welcome back: benjamin 
you have admin privileges 
emacs% java CheckUserName 
enter a user name: foo 
You are not a recognized user emacs%

I have this for the java code

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Scanner;

public class CheckUserName {

    public static void main(String[] args) {
        //users list
        HashSet<String> users = new HashSet<>();
        users.add("liam");
        users.add("noah");
        users.add("william");
        users.add("james");
        users.add("oliver");
        users.add("elijah");
        users.add("lucas");
        users.add("mason");
        users.add("jacob");
        users.add("logan");
        users.add("ethan");
        users.add("michael");
        users.add("henry");
        users.add("sebastian");
        users.add("jackson");
        //admins list
        HashSet<String> admins = new HashSet<>();
        admins.add("benjamin");
        admins.add("alexander");
        admins.add("daniel");
        Scanner sc = new Scanner(System.in);
        System.out.println("enter a user name: ");
        String name = sc.nextLine();
        //checking in users list
        if (users.contains(name.toLowerCase())) {
            System.out.println("Welcome back " + name);
        }
        //checking in admins list
        else if (admins.contains(name.toLowerCase())) {
            System.out.println("Welcome back " + name);
            System.out.println("you have admin privileges ");
        }

        else System.out.println("You are not a recognized user");
    }
}

but I run it, it says "enter a user name:" your output, "enter a user name: welcome back: sebastian" expected output (error with the different names )

Answer 1

import java.util.HashSet;
import java.util.Scanner;

public class CheckUserName {

        public static void main(String[] args) {
                // users list
                HashSet<String> users = new HashSet<>();
                users.add("liam");
                users.add("noah");
                users.add("william");
                users.add("james");
                users.add("oliver");
                users.add("elijah");
                users.add("lucas");
                users.add("mason");
                users.add("jacob");
                users.add("logan");
                users.add("ethan");
                users.add("michael");
                users.add("henry");
                users.add("sebastian");
                users.add("jackson");
                // admins list
                HashSet<String> admins = new HashSet<>();
                admins.add("benjamin");
                admins.add("alexander");
                admins.add("daniel");
                Scanner sc = new Scanner(System.in);
                // need to use print instead of println
                System.out.print("enter a user name: ");
                String name = sc.nextLine();
                // checking in users list
                if (users.contains(name.toLowerCase())) {
                        System.out.println("Welcome back " + name);
                }
                // checking in admins list
                else if (admins.contains(name.toLowerCase())) {
                        System.out.println("Welcome back " + name);
                        System.out.println("you have admin privileges ");
                }

                else
                        System.out.println("You are not a recognized user");
        }
}

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