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Diffstat (limited to 'exercises/101_for5.zig')
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diff --git a/exercises/101_for5.zig b/exercises/101_for5.zig deleted file mode 100644 index 200e71d..0000000 --- a/exercises/101_for5.zig +++ /dev/null @@ -1,126 +0,0 @@ -// -// The 'for' loop is not just limited to looping over one or two -// items. Let's try an example with a whole bunch! -// -// But first, there's one last thing we've avoided mentioning -// until now: The special range that leaves off the last value: -// -// for ( things, 0.. ) |t, i| { ... } -// -// That's how we tell Zig that we want to get a numeric value for -// every item in "things", starting with 0. -// -// A nice feature of these index ranges is that you can have them -// start with any number you choose. The first value of "i" in -// this example will be 500, then 501, 502, etc.: -// -// for ( things, 500.. ) |t, i| { ... } -// -// Remember our RPG characters? They had the following -// properties, which we stored in a struct type: -// -// class -// gold -// experience -// -// What we're going to do now is store the same RPG character -// data, but in a separate array for each property. -// -// It might look a little awkward, but let's bear with it. -// -// We've started writing a program to print a numbered list of -// characters with each of their properties, but it needs a -// little help: -// -const std = @import("std"); -const print = std.debug.print; - -// This is the same character role enum we've seen before. -const Role = enum { - wizard, - thief, - bard, - warrior, -}; - -pub fn main() void { - // Here are the three "property" arrays: - const roles = [4]Role{ .wizard, .bard, .bard, .warrior }; - const gold = [4]u16{ 25, 11, 5, 7392 }; - const experience = [4]u8{ 40, 17, 55, 21 }; - - // We would like to number our list starting with 1, not 0. - // How do we do that? - for (roles, gold, experience, ???) |c, g, e, i| { - const role_name = switch (c) { - .wizard => "Wizard", - .thief => "Thief", - .bard => "Bard", - .warrior => "Warrior", - }; - - std.debug.print("{d}. {s} (Gold: {d}, XP: {d})\n", .{ - i, - role_name, - g, - e, - }); - } -} -// -// By the way, storing our character data in arrays like this -// isn't *just* a silly way to demonstrate multi-object 'for' -// loops. -// -// It's *also* a silly way to introduce a concept called -// "data-oriented design". -// -// Let's use a metaphor to build up an intuition for what this is -// all about: -// -// Let's say you've been tasked with grabbing three glass -// marbles, three spoons, and three feathers from a magic bag. -// But you can't use your hands to grab them. Instead, you must -// use a marble scoop, spoon magnet, and feather tongs to grab -// each type of object. -// -// Now, would you rather use the magic bag: -// -// A. Grouped the items in clusters so you have to pick up one -// marble, then one spoon, then one feather? -// -// OR -// -// B. Grouped the items by type so you can pick up all of the -// marbles at once, then all the spoons, then all of the -// feathers? -// -// If this metaphor is working, hopefully, it's clear that the 'B' -// option would be much more efficient. -// -// Well, it probably comes as little surprise that storing and -// using data in a sequential and uniform fashion is also more -// efficient for modern CPUs. -// -// Decades of OOP practices have steered people towards grouping -// different data types together into mixed-type "objects" with -// the intent that these are easier on the human mind. -// Data-oriented design groups data by type in a way that is -// easier on the computer. -// -// With clever language design, maybe we can have both. -// -// In the Zig community, you may see the difference in groupings -// presented with the terms "Array of Structs" (AoS) versus -// "Struct of Arrays" (SoA). -// -// To envision these two designs in action, imagine an array of -// RPG character structs, each containing three different data -// types (AoS) versus a single RPG character struct containing -// three arrays of one data type each, like those in the exercise -// above (SoA). -// -// For a more practical application of "data-oriented design" -// watch the following talk from Andrew Kelley, the creator of Zig: -// https://vimeo.com/649009599 -// |