-in a hash table, its key data must not be changed. For each hash table,
-you must write two functions that act on keys: a hash function and a
-comparison function. These functions must match the following
-prototypes:
+in a hash table, its key data must not be changed. Instead, if need be,
+remove the element from the hash table, modify its key, then reinsert
+the element.
+
+For each hash table, you must write two functions that act on keys: a
+hash function and a comparison function. These functions must match the
+following prototypes: