Privated firstLetter, New Final

COS225-HW4/src/BookShelf.java

@@ -1,7 +1,7 @@
 import java.util.ArrayList;
 
 public class BookShelf {
-    char firstLetter;
+    private char firstLetter;
     ArrayList<Book> books = new ArrayList<Book>(8);
     public BookShelf() {
         this.firstLetter = ' ';