How do i seperate a String so that "cat!" will be "cat !"

I believe this program will work for most instances except one. I added spaces in indexOF() so words like cathrine and dogsuit lammas Would all be accepted as non profane. The only problem i see is if the user starts the line with cat/dog/llama. CAT! Would show up as non profane because there is no space at the start and there is no space afterwards, is there a String command to spread things out or am i completely on the wrong path?

import java.util.Scanner;
public class ProfanityFilter 
{

 public static void main(String[] args) 
 {

   System.out.println (" welcome to the Profanity filter billboard service ");
   System.out.println (" please enter  a potential sign that contains the words \"cat\", \"dog\" or \"llama\"" );

   Scanner keyboard = new Scanner (System.in);

   String s1 = keyboard.nextLine();

   s1 = s1.toLowerCase();

   if (s1.i开发者_如何学CndexOf(" cat ")!=-1 || s1.indexOf(" dog ") !=-1 || s1.indexOf(" llama ")!=-1)

         System.out.println ("Profanity is in your Billboard");
   else
        System.out.println ("There is no profanity in your Billboard");

 }
}

Regex to the rescue!

if (s1.matches("^.*\\b(cat|dog|llama)\\b.*$"))

Some explanation:

• \b means word boundary
• (a|b|c) means "a or b or c"

You could construct this from an array:

String[] badWords = {"cat", "dog", "llama"};
String regex = "^.*\\b(" + 
    Arrays.toString(badWords).replace(", ", "|").replace("[", "").replace("]", "") + 
    ")\\b.*$";

Take a look at the Pattern class, and \b, which means word boundary.

You should use regular expressions.

You could do as follows that way it will work for "cat" and "horse, cat, and goat" as well.

if(Regex.IsMatch(s1, @"\b(?:cat|dog|llama)\b", RegexOptions.IgnoreCase))
    System.out.println("Profanity is in your Billboard");

Okay, I thought it was C#, but something similar exists in Java.