Question

((Java)) Ask the user for some letters. Display, in alphabetical order, a list of email address domains from users that have a first name that begins with the inputted letters.

A domain is the characters after the @ symbol.

test@domain.com

Standard Input	Files in the same directory
Hea	mock-data.csv

Output
== Domain Lookup ==\n
Enter some letters\n
Here are the domains of the users that begin with Hea\n
free.fr\n
Found 1 domain(s)\n

Standard Input	Files in the same directory
He	mock-data.csv

Output
== Domain Lookup ==\n
Enter some letters\n
Here are the domains of the users that begin with He\n
apple.com\n
artisteer.com\n
cnbc.com\n
free.fr\n
google.it\n
ihg.com\n
indiatimes.com\n
mtv.com\n
myspace.com\n
pbs.org\n
printfriendly.com\n
spiegel.de\n
surveymonkey.com\n
wufoo.com\n
Found 14 domain(s)\n

Standard Input	Files in the same directory
X	mock-data.csv

Output
== Domain Lookup ==\n
Enter some letters\n
Here are the domains of the users that begin with X\n
tumblr.com\n
Found 1 domain(s)\n

Standard Input	Files in the same directory
Fer	mock-data.csv

Output
== Domain Lookup ==\n
Enter some letters\n
Here are the domains of the users that begin with Fer\n
dailymail.co.uk\n
ebay.co.uk\n
indiegogo.com\n
rediff.com\n
unblog.fr\n
Found 5 domain(s)\n

mock-data.csv

Sheilds,Nisse,nsheildsqp@squarespace.com,New York
Lamblin,Codie,clamblinqq@amazon.de,New Jersey
Bagenal,Emlynne,ebagenalqr@wikispaces.com,Texas
Krier,Sacha,skrierqs@youtube.com,South Carolina
Sammonds,Diana,dsammondsqt@smugmug.com,Virginia
Franceschielli,Amara,afranceschielliqu@diigo.com,Texas
Coulston,Nicholas,ncoulstonqv@list-manage.com,Texas
Cadigan,Sampson,scadiganqw@stanford.edu,Georgia
Simanenko,Eleanore,esimanenkoqx@craigslist.org,North Carolina
Jayes,Brooke,bjayesqy@google.com.au,California
Beardsdale,Ferdinanda,fbeardsdaleqz@ebay.co.uk,California
Pandie,Melamie,mpandier0@bravesites.com,Maryland
Dandie,Clement,cdandier1@cloudflare.com,South Carolina
Keenor,Mitchael,mkeenorr2@google.pl,Oklahoma
Joinsey,Cole,cjoinseyr3@360.cn,Texas
Hanington,Warren,whaningtonr4@dmoz.org,Ohio
Bunny,Mose,mbunnyr5@wikimedia.org,Georgia
Streader,Trumann,tstreaderr6@mail.ru,California
Stenning,Hailee,hstenningr7@foxnews.com,Louisiana
Lillywhite,Case,clillywhiter8@mysql.com,California
Derisley,Ethelind,ederisleyr9@nifty.com,Colorado
Carmichael,Raphaela,rcarmichaelra@mayoclinic.com,Kansas
Shurey,Georgie,gshureyrb@mozilla.com,North Carolina
Turpin,Laraine,lturpinrc@accuweather.com,Michigan
Paulus,Tressa,tpaulusrd@jimdo.com,New York
Gon,Heidi,hgonre@mtv.com,Connecticut
Lindroos,Melisse,mlindroosrf@bbc.co.uk,Louisiana
Mathy,Glennis,gmathyrg@answers.com,Ohio
Doul,Joellyn,jdoulrh@fotki.com,Texas
Skellern,Hersch,hskellernri@artisteer.com,New York
Brindley,Griz,gbrindleyrj@census.gov,Virginia
Ghidoli,Georgena,gghidolirk@ted.com,North Dakota
Lyddy,Knox,klyddyrl@blog.com,New Jersey
Osborne,Fidole,fosbornerm@bluehost.com,Minnesota
Chapelhow,Mick,mchapelhowrn@theglobeandmail.com,District of Columbia
Pennini,Filip,fpenniniro@tamu.edu,Texas
Lindsey,Abagael,alindseyrp@zimbio.com,Florida
Birrane,Kaye,kbirranerq@technorati.com,California
Simmens,Anthia,asimmensrr@youtube.com,Delaware

Answer 1

Please let me know if you have any doubts or you want me to modify the answer. And if you find this answer useful then don't forget to rate my answer as thumps up. Thank you! :)

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class Driver implements Comparable<PeopleData> {
    private static String first;
    private static String last;
    private static String email;
    private static String state;

    public static ArrayList<String> loadDatabase() {
        File f = new File("/Users/swapnil/IdeaProjects/DisplayNAme/src/mockdata.txt");
        ArrayList<String> result = new ArrayList<>();
        try {
            Scanner inputFile = new Scanner(f);

            while (inputFile.hasNextLine()) {

                String[] temp = inputFile.nextLine().split(",");
                first = temp[0];
                last = temp[1];
                email = temp[2];
                state = temp[3];

                result.add(String.valueOf(new PeopleData(first, last, email, state)));

            }

        } catch (FileNotFoundException e) {
            System.out.println("File is not found!");
        }
        return result;
    }

    public static String searchLetter(String search){
        if (getFirst().contains(search)){

        }
        return email;
    }
    public static String getFirst(){
        return first;
    }

    public static void main(String[] args){
        ArrayList<String> data = new ArrayList<>();
        loadDatabase();
        Scanner keyboard = new Scanner(System.in);

        System.out.println("== Domain Lookup ==");
        System.out.println("Enter some letters");

        System.out.println(data.size());
        System.out.println(data);
        String search = keyboard.nextLine();

        System.out.println(searchLetter(search));

    }

    @Override
    public int compareTo(PeopleData o) {
        return 0;
    }
}

----------------------------------------------------------------------------------------------------------------------------------
public class PeopleData {

    private String first;
    private String last;
    private String email;
    private String state;

    public PeopleData(String first, String last, String email, String state) {
        this.first = first;
        this.last = last;
        this.email = email;
        this.state = state;
    }
}

DisplayNAme /ldeaProjects/DisplayNAme] - .../src/Driver.java [DisplayNAme] ,DisplayNAme-src ƠDriver G Driverjava 렙 mockdata.txt . @ PeopleData.java Project * ÷ '嶚. I← import java.io.File import java.io.FiLeNotFoundException import java.util.ArrayList; import java.utit.scanner; DisplayNAme IdeaProjects/DisplayNAme idea out | public class Driver implements Comparable-PeopleData» { 6 Driver private static String first private static String last private static String email: private static String state mockdata.txt DisplayNAme.iml ▶ llll External Libraries 12 Scratches and Consoles public static ArrayList <String loadDatabase() File f = new Filel pathname. "/Users/swapnal/IdeaProjects/DisplayNAme/src/mackdata. txt"); ArrayList<Stringo result new ArrayListo); try t 15 16 Scanner inputFile = new Scanner(f); 18 while (inputFile.haslextLine)) 20 21 23 25 Stringl1 temp inputFile.nextLine().split( regex first temp [e]: last temp[1] email = temp [2]; state temp [3] 26 result.add(String.valueof(new PeopleData(first, last, email, state))) 30 /Library/Java/JavaVirtuaMachines/jdk-9.0.4.jdk/Contents/Home/bin/java "-javaagent:/Applications/IntelliJ IDEA CE.app/Contents/Lib/idea_rt.jar-51386:/Applications/IntelliJ IDEA CE.app/Contents/bi == Domain Lookup = Enter some letters Il Eb Meriel's asinnensrr@youtube.com enail is Process finished with exit code 0 H Loaded classes are up to date. Nothing to reload. (moments ago