part 05: clarify exercise

[rust-101.git] / src / part05.rs

diff --git a/src/part05.rs b/src/part05.rs
index 72c787d00c7ef7c518f4fb1b7e5ff700b8f8eed0..b3b428ec03c67d65e155d1d33fa23d7d34594554 100644 (file)
--- a/src/part05.rs
+++ b/src/part05.rs
@@ -10,7 +10,7 @@
 //@ to use a vector "digits" of the number. This is like "1337" being a vector of four digits (1, 3, 3, 7),
 //@ except that we will use `u64` as type of our digits, meaning we have 2^64 individual digits. Now we just
 //@ have to decide the order in which we store numbers. I decided that we will store the least significant
-//@ digit first. This means that "1337" would actually become (7, 3, 3, 1).<br/>
+//@ digit first. This means that "1337" would actually become (7, 3, 3, 1). <br/>
 //@ Finally, we declare that there must not be any trailing zeros (corresponding to
 //@ useless leading zeros in our usual way of writing numbers). This is to ensure that
 //@ the same number can only be stored in one way.
@@ -111,7 +111,7 @@ impl<T: Clone> Clone for SomethingOrNothing<T> {
 //@ `#[derive(Clone)]` right before the definition of `SomethingOrNothing`.
 
 // **Exercise 05.2**: Write some more functions on `BigInt`. What about a function that returns the number of
-// digits? The number of non-zero digits? The smallest/largest digit?
+// digits? The number of non-zero digits? The smallest/largest digit? Of course, these should all just borrow `self`.
 
 // ## Mutation + aliasing considered harmful (part 2)
 //@ Now that we know how to borrow a part of an `enum` (like `v` above), there's another example for why we
@@ -131,7 +131,7 @@ fn work_on_variant(mut var: Variant, text: String) {
         Variant::Number(ref mut n) => ptr = n,
         Variant::Text(_) => return,
     }
-    /* var = Variant::Text(text); */
+    /* var = Variant::Text(text); */                                /* BAD! */
     *ptr = 1337;
 }
 //@ Now, imagine what would happen if we were permitted to also mutate `var`. We could, for example,