diff options
| -rw-r--r-- | build.zig | 11 | ||||
| -rw-r--r-- | exercises/48_methods2.zig | 6 | ||||
| -rw-r--r-- | exercises/49_quiz6.zig | 91 | ||||
| -rw-r--r-- | patches/patches/49_quiz6.patch | 11 |
4 files changed, 112 insertions, 7 deletions
@@ -252,11 +252,14 @@ const exercises = [_]Exercise{ }, .{ .main_file = "48_methods2.zig", - .output = "Elephant A (U). Elephant B (U). Elephant C (U).", - .hint = "This just needs one little fix." + .output = "A B C", + .hint = "This just needs one little fix.", + }, + .{ + .main_file = "49_quiz6.zig", + .output = "A B C Cv Bv Av", + .hint = "Now you're writting Zig!", }, - // 48 use struct method for elephant tails - // 49 quiz: add elephant trunk (like tail)! // 50 null vs undefined // 51 pass-by-value and const fn params // 52 slices! diff --git a/exercises/48_methods2.zig b/exercises/48_methods2.zig index b9477da..37b182c 100644 --- a/exercises/48_methods2.zig +++ b/exercises/48_methods2.zig @@ -23,9 +23,9 @@ const Elephant = struct { } pub fn print(self: *Elephant) void { - // Prints elephant letter and (V)isited or (U)nvisited. - var v: u8 = if (self.visited) 'V' else 'U'; - std.debug.print("Elephant {u} ({u}). ", .{ self.letter, v}); + // Prints elephant letter and [v]isited + var v: u8 = if (self.visited) 'v' else ' '; + std.debug.print("{u}{u} ", .{ self.letter, v }); } }; diff --git a/exercises/49_quiz6.zig b/exercises/49_quiz6.zig new file mode 100644 index 0000000..a1a1dec --- /dev/null +++ b/exercises/49_quiz6.zig @@ -0,0 +1,91 @@ +// +// "Trunks and tails +// Are handy things" + +// from Holding Hands +// by Lenore M. Link +// +// Now that we have tails all figured out, can you implement trunks? +// +const std = @import("std"); + +const Elephant = struct { + letter: u8, + tail: ?*Elephant = null, + trunk: ?*Elephant = null, + visited: bool = false, + + // Elephant tail methods! + pub fn getTail(self: *Elephant) *Elephant { + return self.tail.?; // Remember, this is means "orelse unreachable" + } + + pub fn hasTail(self: *Elephant) bool { + return (self.tail != null); + } + + // Your Elephant trunk methods go here! + // --------------------------------------------------- + + ??? + + // --------------------------------------------------- + + pub fn visit(self: *Elephant) void { + self.visited = true; + } + + pub fn print(self: *Elephant) void { + // Prints elephant letter and [v]isited + var v: u8 = if (self.visited) 'v' else ' '; + std.debug.print("{u}{u} ", .{ self.letter, v }); + } +}; + +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; + + // And link the elephants so that each trunk "points" to the previous. + elephantB.trunk = &elephantA; + elephantC.trunk = &elephantB; + + visitElephants(&elephantA); + + std.debug.print("\n", .{}); +} + +// This function visits all elephants twice, tails to trunks. +fn visitElephants(first_elephant: *Elephant) void { + var e = first_elephant; + + // Follow the tails! + while (true) { + e.print(); + e.visit(); + + // Get the next elephant or stop. + if (e.hasTail()) { + e = e.getTail(); + } else { + break; + } + } + + // Follow the trunks! + while (true) { + e.print(); + + // Get the previous elephant or stop. + if (e.hasTrunk()) { + e = e.getTrunk(); + } else { + break; + } + } +} diff --git a/patches/patches/49_quiz6.patch b/patches/patches/49_quiz6.patch new file mode 100644 index 0000000..83f9faf --- /dev/null +++ b/patches/patches/49_quiz6.patch @@ -0,0 +1,11 @@ +28a29,31 +> pub fn getTrunk(self: *Elephant) *Elephant { +> return self.trunk.?; +> } +30,31c33,35 +< ??? +< +--- +> pub fn hasTrunk(self: *Elephant) bool { +> return (self.trunk != null); +> } |