Add comments to qsort example

This will be used to smoke test comment inserter.

Author: thedataking

examples/qsort/qsort.c

@@ -5,26 +5,37 @@ void swap(int* a, int* b)
     *b = t;
 }
 
+/* 
+ * Lomuto Partition Scheme:
+ * Partitions the array so that elements < pivot are on the left, 
+ * and elements >= pivot are on the right.
+ */
 int partition (int arr[], int low, int high)
 {
+    // Partition the subarray around the last element as pivot and return pivot's final index.
     int pivot = arr[high];
     int i = low - 1;
 
     for (int j = low; j <= high - 1; j++) {
         if (arr[j] <= pivot) {
             i++;
+            // Move elements <= pivot into the left partition.
             swap(&arr[i], &arr[j]);
         }
     }
+    // Place pivot just after the final element of the left partition.
     swap(&arr[i + 1], &arr[high]);
     return i + 1;
 }
 
 void quickSort(int arr[], int low, int high)
 {
     if (low < high) {
-        int i = partition(arr, low, high);
-        quickSort(arr, low, i - 1);
-        quickSort(arr, i + 1, high);
+        /* pi is the partitioning index; arr[pi] is now at the right place */
+        int pi = partition(arr, low, high);
+
+        /* Recursively sort elements before and after partition */
+        quickSort(arr, low, pi - 1);
+        quickSort(arr, pi + 1, high);
     }
 }