mention builtin ex coming up

1 files changed, 3 insertions, 0 deletions

diff --git a/exercises/016_for2.zig b/exercises/016_for2.zig
index 0a62a1a..1d4496a 100644
--- a/exercises/016_for2.zig
+++ b/exercises/016_for2.zig
@@ -25,6 +25,9 @@ pub fn main() void {
     //
     // See if you can figure out the missing piece:
     for (bits) |bit, ???| {
+        // Note that we convert the usize i to a u32 with
+        // @intCast(), a builtin function just like @import().
+        // We'll learn about these properly in a later exercise.
         var place_value = std.math.pow(u32, 2, @intCast(u32, i));
         value += place_value * bit;
     }