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Diffstat (limited to 'exercises/46_optionals2.zig')
-rw-r--r-- | exercises/46_optionals2.zig | 58 |
1 files changed, 0 insertions, 58 deletions
diff --git a/exercises/46_optionals2.zig b/exercises/46_optionals2.zig deleted file mode 100644 index d3f65bb..0000000 --- a/exercises/46_optionals2.zig +++ /dev/null @@ -1,58 +0,0 @@ -// -// Now that we have optional types, we can apply them to structs. -// The last time we checked in with our elephants, we had to link -// all three of them together in a "circle" so that the last tail -// linked to the first elephant. This is because we had NO CONCEPT -// of a tail that didn't point to another elephant! -// -// We also introduce the handy ".?" shortcut: -// -// const foo = bar.?; -// -// is the same as -// -// const foo = bar orelse unreachable; -// -// See if you can find where we use this shortcut below. -// -// Now let's make those elephant tails optional! -// -const std = @import("std"); - -const Elephant = struct { - letter: u8, - tail: *Elephant = null, // Hmm... tail needs something... - visited: bool = false, -}; - -pub fn main() void { - var elephantA = Elephant{ .letter = 'A' }; - var elephantB = Elephant{ .letter = 'B' }; - var elephantC = Elephant{ .letter = 'C' }; - - // Link the elephants so that each tail "points" to the next. - elephantA.tail = &elephantB; - elephantB.tail = &elephantC; - - visitElephants(&elephantA); - - std.debug.print("\n", .{}); -} - -// This function visits all elephants once, starting with the -// first elephant and following the tails to the next elephant. -fn visitElephants(first_elephant: *Elephant) void { - var e = first_elephant; - - while (!e.visited) { - std.debug.print("Elephant {u}. ", .{e.letter}); - e.visited = true; - - // We should stop once we encounter a tail that - // does NOT point to another element. What can - // we put here to make that happen? - if (e.tail == null) ???; - - e = e.tail.?; - } -} |