"999 is enough for anybody" triple-zero padding (#18)

When I hit 999 exercises, I will finally have reached the ultimate
state of soteriological release and no more exercises will be needed.
The cycle will be complete. All that will be left is perfect quietude,
freedom, and highest happiness.

1 files changed, 82 insertions, 0 deletions

diff --git a/exercises/043_pointers5.zig b/exercises/043_pointers5.zig
new file mode 100644
index 0000000..cb94189
--- /dev/null
+++ b/exercises/043_pointers5.zig
@@ -0,0 +1,82 @@
+//
+// Passing integer pointers around is generally not something you're going
+// to do. Integers are cheap to copy.
+//
+// But you know what IS useful? Pointers to structs:
+//
+//     const Vertex = struct{ x: u32, y: u32, z: u32 };
+//
+//     var v1 = Vertex{ .x=3, .y=2, .z=5 };
+//
+//     var pv: *Vertex = &v1;   // <-- a pointer to our struct
+//
+// Note that you don't need to dereference the "pv" pointer to access
+// the struct's fields:
+//
+//     YES: pv.x
+//     NO:  pv.*.x
+//
+// We can write functions that take pointer arguments:
+//
+//     fn foo(v: *Vertex) void {
+//         v.x += 2;
+//         v.y += 3;
+//         v.z += 7;
+//     }
+//
+// And pass references to them:
+//
+//     foo(&v1);
+//
+//
+// Let's revisit our RPG example and make a printCharacter() function
+// that takes a Character pointer.
+//
+const std = @import("std");
+
+const Class = enum {
+    wizard,
+    thief,
+    bard,
+    warrior,
+};
+
+const Character = struct {
+    class: Class,
+    gold: u32,
+    health: u8 = 100, // <--- You can also provide fields a default value!
+    experience: u32,
+};
+
+pub fn main() void {
+    var glorp = Character{
+        .class = Class.wizard,
+        .gold = 10,
+        .experience = 20,
+    };
+
+    // FIX ME!
+    // Please pass our Character "glorp" to printCharacter():
+    printCharacter(???);
+}
+
+// Note how this function's "c" parameter is a pointer to a Character struct.
+fn printCharacter(c: *Character) void {
+
+    // Here's something you haven't seen before: when switching an enum, you
+    // don't have to write the full enum name. Zig understands that ".wizard"
+    // means "Class.wizard" when we switch on a Class enum value:
+    const class_name = switch (c.class) {
+        .wizard => "Wizard",
+        .thief => "Thief",
+        .bard => "Bard",
+        .warrior => "Warrior",
+    };
+
+    std.debug.print("{s} (G:{} H:{} XP:{})", .{
+        class_name,
+        c.gold,
+        c.health,
+        c.experience,
+    });
+}