I'm working on a assignment in my com s class which requires me to create a wheel of fortune game. I'm currently working on the `getDisplayedPhrase` method which I will explain. So for this program I have a random phrase for example  

`"this is a question, thanks for helping!"`  

I want this phrase to change to  

`"**** ** * ********, ****** *** *******!"`  

This is how the phrase should look like before they guess it. As you can see I'm trying to only change the letters so I created a 

```
private static final String alpha ="abcdefghijklmnopqrstuvwxyz" 

```

to avoid any punctuation. 
This is what I have so far:

```
public String getDisplayedPhrase() {
    for (int i = 0; i<secretPhrase.length(); i++){
        I don't know what to put here and what method to use???
                I'm thinking of using charAt() or indexOf()
    }
    return displayedPhrase;
}

```