title: I'm stuck on "3.8.12: Replace Letter" in Java on CodeHS
body: <p>The instructions are to: </p>
  
  <p>Write a method that replaces all instance of one letter with another.</p>
  
  <p>For example,</p>
  
  <pre><code>replaceLetter("hello", 'l', 'y')
  </code></pre>
  
  <p>returns</p>
  
  <pre><code>"heyyo"
  </code></pre>
  
  <hr>
  
  <p>I'm not even sure where to start but I've got this so far:</p>
  
  <pre><code>String str = "Hello world";
  System.out.println (str);
  str = str.replace("l", "y");
  System.out.println (str);
  </code></pre>
  
  <p>But I have to get my actual method to look like this: </p>
  
  <pre><code>public String replaceLetter(String word, char letterToReplace, char replacingLetter)
  </code></pre>
  
  <p>so inputing any string would work, not just "Hello world" which I used as a test.</p>