diff --git a/Exercise_23/Exercise_23_04/Exercise_23_04.class b/Exercise_23/Exercise_23_04/Exercise_23_04.class
index 9c811b22..917bbe06 100644
Binary files a/Exercise_23/Exercise_23_04/Exercise_23_04.class and b/Exercise_23/Exercise_23_04/Exercise_23_04.class differ
diff --git a/Exercise_23/Exercise_23_04/Exercise_23_04.java b/Exercise_23/Exercise_23_04/Exercise_23_04.java
index 2553d9f3..af9f7373 100644
--- a/Exercise_23/Exercise_23_04/Exercise_23_04.java
+++ b/Exercise_23/Exercise_23_04/Exercise_23_04.java
@@ -20,9 +20,15 @@ public static void quickSort(int[] list, int first, int last) {
 	public static int partition(int[] list, int first, int last) {
 		int middle = list[(list.length - 1) / 2];
 		// choose the median element as the pivot
-		int pivot = median(first, middle, last); 
+		// here should parse the element in the list instead of
+                // index;
+                int pivot = median(list[first], middle, list[last]); 
 		int low = first + 1; // Index for forward search
-		int high = last; // Index for backward search
+		                     // here should not forward the index
+                                     // the pivot is choose from median() 
+                                     // instead of the first element in
+                                     // the list
+                int high = last; // Index for backward search
 
 		while (high > low) {
 			// Search forward from left
@@ -69,4 +75,4 @@ public static int median(int first, int middle, int last) {
 		return Math.max(Math.min(first, middle), 
 			Math.min(Math.max(first, middle), last));
 	}
-}
\ No newline at end of file
+}