55 lines
1.7 KiB
Zig
55 lines
1.7 KiB
Zig
//
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// We've seen that passing arrays around can be awkward. Perhaps you
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// remember a particularly horrendous function definition from quiz3?
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// This function can only take arrays that are exactly 4 items long!
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//
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// fn printPowersOfTwo(numbers: [4]u16) void { ... }
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//
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// That's the trouble with arrays - their size is part of the data
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// type and must be hard-coded into every usage of that type. This
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// digits array is a [10]u8 forever and ever:
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//
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// var digits = [10]u8{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
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//
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// Thankfully, Zig has slices, which let you dynamically point to a
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// start item and provide a length. Here are slices of our digit
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// array:
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//
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// const foo = digits[0..1]; // 0
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// const bar = digits[3..9]; // 3 4 5 6 7 8
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// const baz = digits[5..9]; // 5 6 7 8
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// const all = digits[0..]; // 0 1 2 3 4 5 6 7 8 9
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//
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// As you can see, a slice [x..y] starts with the index of the
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// first item at x and the last item at y-1. You can leave the y
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// off to get "the rest of the items".
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//
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// The type of a slice on an array of u8 items is []u8.
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//
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const std = @import("std");
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pub fn main() void {
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var cards = [8]u8{ 'A', '4', 'K', '8', '5', '2', 'Q', 'J' };
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// Please put the first 4 cards in hand1 and the rest in hand2.
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const hand1: []u8 = cards[0..4];
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const hand2: []u8 = cards[4..];
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std.debug.print("Hand1: ", .{});
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printHand(hand1);
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std.debug.print("Hand2: ", .{});
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printHand(hand2);
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}
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// Please lend this function a hand. A u8 slice hand, that is.
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fn printHand(hand: []u8) void {
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for (hand) |h| {
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std.debug.print("{u} ", .{h});
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}
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std.debug.print("\n", .{});
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}
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//
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// Fun fact: Under the hood, slices are stored as a pointer to
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// the first item and a length.
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