secondaryWordCount method added

Others/CountWords.java

@@ -16,6 +16,7 @@ public class CountWords {
         String str = input.nextLine();
 
         System.out.println("Your text has " + wordCount(str) + " word(s)");
+        System.out.println("Your text has " + secondaryWordCount(str) + " word(s)");
         input.close();
     }
 
@@ -25,4 +26,25 @@ public class CountWords {
         return s.trim().split("[\\s]+").length;
     }
 
+    /**
+     * counts the number of words in a sentence but ignores all potential
+     * non-alphanumeric characters that do not represent a word. runs in O(n) where
+     * n is the length of s
+     * 
+     * @param s String: sentence with word(s)
+     * @return int: number of words
+     */
+    private static int secondaryWordCount(String s) {
+        if (s == null || s.isEmpty())
+            return 0;
+        StringBuilder sb = new StringBuilder();
+        for (char c : s.toCharArray()) {
+            if (Character.isLetter(c) || Character.isDigit(c))
+                sb.append(c);
+        }
+        s = sb.toString();
+        return s.trim().split("[\\s]+").length;
+
+    }
+
 }