How do you double each letter in a string using a for loop and an if statement in java
<p>I need to double each letter in a string using a for loop and an if-then statement. How can you comb through a string and test if each character is a letter or a symbol like an exclamation point? And then print the string back out with each letter doubled and each exclamation point tripled.</p>

<p>This is what I have so far. It's unfinished and it doesn't work at all, but am I on the right track?</p>

<pre><code>import java.util.Scanner;

public class DoubleLetters{
  public static void main(String[] args){
  Scanner scan = new Scanner(System.in);

  System.out.println("Enter a sentence:");
  String sentence = scan.nextLine();

  boolean isLetter = false;

  for (int i = 0; i &lt; sentence.length(); i++){
    isLetter = Character.isLetter(sentence.charAt(i));
    if (i == sentence.length() || sentence.charAt(i) == ' ' || isLetter == false){
    System.out.print(sentence.charAt(i) + sentence.charAt(i));
  }
}
</code></pre>