[coco]

I don't quite understand your question, but I'll give some advice.

Code:

String word = hello;

for(int i = 0; i < word.length; i++)
{
   word.replace(word[i], "*");
}

If my code above is syntactically correct, that will replace all letters in "word" with *. But since you've changed "hello" to "*****" you've lost the secret word completely. Maybe you want something like...

Code:

String word = hello;
String coverUpWord = '';

for(int i = 0; i < word.length; i++)
{
   coverUpWord += '*';
}

Now both the above use for-loops not while-loops, but they are essentially the same. Why is it that you can't use a while-loop?

Greetings.