How to concatenate two strings in java?

Question

So I have to get the users first and last name which I have but then I have to take the first letter of the persons first name and concatenate it to the last name to create a username (all lowercase)

but I'm stuck on how to add that... Im assuming I have to use one of the methods from the string class but I'm not exactly sure which one or how to do it?

 package userinput.java;
 import java.util.Scanner;

 public class UserinputJava {


 public static void main(String[] args) 
  {
   Scanner userInput = new Scanner (System.in);

   String firstname;
   String lastname;
   String fullname;

   System.out.print("Enter first name: ");
   firstname = userInput.next();

   System.out.print("Enter last name: ");
   lastname = userInput.next();


   fullname = firstname + lastname;
   System.out.println ("You are " + fullname + "!");




  }

 }

Already Discussed in the following thread http://stackoverflow.com/a/47628/2088039 — Tonino, May 05 '14 at 15:16

score 3 · Answer 1 · answered May 05 '14 at 15:16

3

String fullname = firstname.charAt(0) + lastname;

Better yet, use a StringBuilder.

EDIT: Actually it's not better because the compiler converts the above line to the line below automatically. The above line is more readable.

String fullname = new StringBuilder().append(firstname.charAt(0)).append(lastname).toString();

answered May 05 '14 at 15:16

Anubian Noob

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1

Using a StringBuilder would be overkill to append one character - but the compiler does it for you anyway, so the first version is actually better IMO. – assylias May 05 '14 at 15:18
Good point, I forgot that. – Anubian Noob May 05 '14 at 15:18
where do i place the String fullname = firstname.charAt(0) + lastname; – marie May 05 '14 at 15:19
1

@marie please have a guess ;) – Joffrey May 05 '14 at 15:20
haha i tried! but its showing up as an error i figured it would be where i have the other strings listed – marie May 05 '14 at 15:21
@marie use that once your strings contain something, therefore in place of your current `fullname = firstname + lastname;` – Joffrey May 05 '14 at 15:23
Replace the line `fullname = firstname + lastname;` with `fullname = firstname.charAt(0) + lastname;` – Anubian Noob May 05 '14 at 15:24
oops i had that but i just realized i had charAt like CharAt thats why it wasn't reading it... thank you!! – marie May 05 '14 at 15:26

score 1 · Answer 2 · answered May 05 '14 at 15:18

You can use the charAt method to extract the first (or any other) character of a string. Note that charAt returns a char primitive, not a String, so it's more convenient to use a StringBuilder:

StringBuilder sb = new StringBuilder (lastname.length() + 1);
sb.append(firstname.charAt(0));
sb.append(lastname);
String userName = sb.toString().toLowerCase();

How to concatenate two strings in java?

2 Answers2