Replace Random Positions in a String

[Zamfir Adrian]

Hello guys, I'm working to a system called Quiz ...

The last thing that remains are the 'clues'. In present i have

   <id value="100"> 
      <question value="Who said E=mc2"/> 
      <answear value="Einstein"/> 
      <clue1 value="E*******"/> 
      <clue2 value="E******n"/> 
      <clue3 value="Ei****in"/> 
   </id> 

and I want to remove from xml the clues because is hard to do them manually ...
so I made something but i failed

public class Test 
{
	public static void main(String[] argv) throws Exception 
	{
		System.out.println(replaceSubString("Einstein", "*", 3));
	}

	static String[] letters = {"e","i"};
	
	public static String replaceSubString(final String str, final String newToken, int max) 
	{
		if ((str == null) || (newToken == null)) 
		return str;
		
		StringBuffer buf = new StringBuffer(str.length());
		int start = 0, end = 0;
		
		for(int i = 0; i < letters.length; i++)
		{
			if(Rnd.get(100) > 50) //50% to add the symbol
			{
				while ((end = str.indexOf(letters[i], start)) != -1) 
				{
					buf.append(str.substring(start, end)).append(newToken);
					start = end + 1;
					if (--max == 0) 
						break;
				}
			}
		}
		
		buf.append(str.substring(start));
		return buf.toString();
	}
}

if someone offers to help me I would be very grateful..

-Thanks !

[fred rosenberger]

Can you be more specific than "I failed"? Does your code compile? Do you get error messages? Does it crash when it runs? THe more information you give us, the easier it is to help you (and folks are more likely to do so).

[Zamfir Adrian]

fred rosenberger wrote:Can you be more specific than "I failed"? Does your code compile? Do you get error messages? Does it crash when it runs? THe more information you give us, the easier it is to help you (and folks are more likely to do so).

oh, sorry..I didn't received an error...

Compile Resutl => 'Einst*in'

the loop doesn't work.. idk .. only the first letter from array is replaced...

[Rob Spoor]

You're using some random thingy (Rnd) to determine whether or not to replace. Perhaps for "e" (one occurrence) it returned something over 50 and for "i" it didn't?
I've tried your code (using another random number returning method instead of Rnd.get) and I got "Einstein", "E*nste*n", "Einst*in", "Einst**n" and more results like that.

That last one is because you never reset start and end when you get a new letter. That means that when you replace "e" first, the next replacement will only start after that. Perhaps you can use a StringBuilder (not StringBuffer) instead for the entire contents, then replacing only that part:

        StringBuilder sb = new StringBuilder(str);
        for(int i = 0; i < letters.length; i++)
        {
            if(get(100) > 50) //50% to add the symbol
            {
                int index = 0;
                while ((index = sb.indexOf(letters[i], index)) != -1)
                {
                    sb.replace(index, index + 1, newToken);
                    index++;
                    if (--max == 0)
                        break;
                }
            }
        }
    }
    return sb.toString();

Oh, and UseRealWords: "I don't know" instead of "idk".

[Zamfir Adrian]

I am grateful, Thanks!

[Rob Spoor]

Check my update.

[Zamfir Adrian]

Rob Spoor wrote:Check my update.

I already did, thanks again