Thread: URGENT HOMEWORK HELP!

So for my homework I am supposed to create a program that allows a user to input a Twitter/Facebook status with a mention (@), a hashtag (#) and a URL link to some website. The program is supposed to recognize these three things, extract them and display them as follows:
hashtag: homework
usertag: Mary
URL: http://www.facebook.com/NikolaCS110

We are also supposed to use the ternary operator, but I'm stumped as to how to incorporate that. This is what I have so far, but I am seriously stuck! I've tried to just run the program with it recognizing and printing out just the #, but it gives me an error message which I assume will happen for the other two things

here's what I have so far

 
import java.util.Scanner;
public class SocialMedia {
	public static void main (String [] args){
		Scanner input = new Scanner(System.in);
		String userStatus = null;
		String userTag = null;
		String userHashtag = null;
		String userUrl = null;
		int mention = 0;
		int hashtag = 0;
		int link = 0;
 
		System.out.println("Enter a status with a link, a hashtag, and a mention");
		userStatus = input.nextLine();
 
		mention = userStatus.lastIndexOf('@');
		hashtag = userStatus.lastIndexOf("#");
		link = userStatus.lastIndexOf(':')
 
 
                 userHashtag = userStatus.substring(hashtag);
 
		System.out.println("hashtag:" + userHashtag);

and here is the error message
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.String.substring(Unknown Source)
at SocialMedia.main(SocialMedia.java:22)

Try to figure out where the -1 come from

I fixed the error message by changing the substring to

 userHashtag = userStatus.substring(0,hashtag +1);

, but it wont display the text after the #

Originally Posted by mpagudelo

I fixed the error message by changing the substring to

 userHashtag = userStatus.substring(0,hashtag +1);

, but it wont display the text after the #

That does not solve the problem, it patches the symptom.
Figure out where the -1 come from to begin with.