Question

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();
    }
}

Compile Result => ‘Einst*in’

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

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

-Thanks !

Answer 1

How about something like this?

public String generatClue(String answer,int level){
    if(level >= answer.length()/2)
        return answer.replaceAll("[^ ]","*");

    return answer.substring(0,level)
      + answer.substring(level,answer.length()-level).replaceAll("[^ ]","*")
      + answer.substring(answer.length()-level);
}

Output:

generateClue("Einstein",1);
=> E******n
generateClue("Einstein",3);
=> Ein**ein
generateClue("Einstein",4)
=> Einstein
generateClue("Hans Christian Andersen",4)
=> Hans ********* ****rsen

EDIT: Here’s one for random characters in the string:

public String generatClue2(String answer,int level){
    if(answer.length()==level)
        return answer.replaceAll("[^ ]","*");

    Random rand=new Random();

    for(int i=0; i<level; ++i){
        char c;
        int n;
        do{
            n=rand.nextInt(answer.length());
            c=answer.charAt(n);
        }
        while(c == ' ' || c == '*');
        answer = answer.substring(0,n) + '*' + answer.substring(n+1);
    }
    return answer;
}

Output:

generateClue2("Hans Christian Andersen",4);
=> Han* C*ri*tian Ande*sen
generateClue2("Hans Christian Andersen",4);
=> *ans Chr*sti*n An*ersen
generateClue2("Hans Christian Andersen",17);
=> H**s ******i** ***e****
generateClue2("Hans Christian Andersen",23);
=> **** ********* ********