diff options
| -rw-r--r-- | build.zig | 5 | ||||
| -rw-r--r-- | exercises/52_slices.zig | 49 | ||||
| -rw-r--r-- | patches/patches/52_slices.patch | 10 |
3 files changed, 63 insertions, 1 deletions
@@ -268,7 +268,10 @@ const exercises = [_]Exercise{ .main_file = "51_values.zig", .output = "1:false!. 2:true!. 3:true!. XP before:0, after:200.", }, - // 52 slices! + .{ + .main_file = "52_slices.zig", + .output = "Hand1: A 4 K 8 Hand2: 5 2 Q J", + }, }; /// Check the zig version to make sure it can compile the examples properly. diff --git a/exercises/52_slices.zig b/exercises/52_slices.zig new file mode 100644 index 0000000..98177cd --- /dev/null +++ b/exercises/52_slices.zig @@ -0,0 +1,49 @@ +// +// We've seen that passing arrays around can be awkward. Perhaps you +// remember a particularly horrendous function definition from quiz3? +// This function can only take arrays that are exactly 4 items long! +// +// fn printPowersOfTwo(numbers: [4]u16) void { ... } +// +// That's the trouble with arrays - their size is part of the data +// type and must be hard-coded into every usage of that type. This +// digits array is a [10]u8 forever and ever: +// +// var digits = [10]u8{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; +// +// Thankfully, Zig has slices, which let you dynamically point to a +// start item and provide a length. Here are slices of our digit +// array: +// +// const foo = digits[0..1]; // 0 +// const bar = digits[3..9]; // 3 4 5 6 7 8 +// const all = digits[0..]; // 0 1 2 3 4 5 6 7 8 9 +// +// As you can see, a slice [x..y] defines a first item by index x and +// a length y (where y-1 is the index of the last item). Leaving y off +// gives you the rest of the items. +// +// Notice that the type of a slice on an array of u8 items is []u8. +// +const std = @import("std"); + +pub fn main() void { + var cards = [8]u8{ 'A', '4', 'K', '8', '5', '2', 'Q', 'J' }; + + // Please put the first 4 cards in hand1 and the rest in hand2. + const hand1: []u8 = cards[???]; + const hand2: []u8 = cards[???]; + + std.debug.print("Hand1: ", .{}); + printHand(hand1); + + std.debug.print("Hand2: ", .{}); + printHand(hand2); +} + +// Please lend this function a hand. A u8 slice hand, that is. +fn printHand(hand: ???) void { + for (hand) |h| { + std.debug.print("{u} ", .{h}); + } +} diff --git a/patches/patches/52_slices.patch b/patches/patches/52_slices.patch new file mode 100644 index 0000000..80f8d72 --- /dev/null +++ b/patches/patches/52_slices.patch @@ -0,0 +1,10 @@ +34,35c34,35 +< const hand1: []u8 = cards[???]; +< const hand2: []u8 = cards[???]; +--- +> const hand1: []u8 = cards[0..4]; +> const hand2: []u8 = cards[4..]; +45c45 +< fn printHand(hand: ???) void { +--- +> fn printHand(hand: []u8) void { |