6ad9774189
When I hit 999 exercises, I will finally have reached the ultimate state of soteriological release and no more exercises will be needed. The cycle will be complete. All that will be left is perfect quietude, freedom, and highest happiness.
72 lines
2 KiB
Zig
72 lines
2 KiB
Zig
//
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// Now that we've seen how methods work, let's see if we can help
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// our elephants out a bit more with some Elephant methods.
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//
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const std = @import("std");
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const Elephant = struct {
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letter: u8,
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tail: ?*Elephant = null,
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visited: bool = false,
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// New Elephant methods!
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pub fn getTail(self: *Elephant) *Elephant {
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return self.tail.?; // Remember, this is means "orelse unreachable"
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}
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pub fn hasTail(self: *Elephant) bool {
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return (self.tail != null);
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}
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pub fn visit(self: *Elephant) void {
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self.visited = true;
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}
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pub fn print(self: *Elephant) void {
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// Prints elephant letter and [v]isited
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var v: u8 = if (self.visited) 'v' else ' ';
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std.debug.print("{u}{u} ", .{ self.letter, v });
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}
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};
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pub fn main() void {
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var elephantA = Elephant{ .letter = 'A' };
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var elephantB = Elephant{ .letter = 'B' };
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var elephantC = Elephant{ .letter = 'C' };
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// Link the elephants so that each tail "points" to the next.
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elephantA.tail = &elephantB;
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elephantB.tail = &elephantC;
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visitElephants(&elephantA);
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std.debug.print("\n", .{});
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}
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// This function visits all elephants once, starting with the
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// first elephant and following the tails to the next elephant.
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fn visitElephants(first_elephant: *Elephant) void {
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var e = first_elephant;
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while (true) {
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e.print();
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e.visit();
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// Get the next elephant or stop.
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if (e.hasTail()) {
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e = e.???; // Which method do we want here?
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} else {
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break;
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}
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}
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}
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// Bonus: Zig's enums can also have methods! Can you find
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// one in the wild? If you can, mention it along with your
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// name or alias in a comment below this one and make a
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// pull request on GitHub for a piece of eternal Ziglings
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// glory. The first five (5) PRs will be accepted!
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//
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// 1) drforester - I found one in the Zig source:
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// https://github.com/ziglang/zig/blob/041212a41cfaf029dc3eb9740467b721c76f406c/src/Compilation.zig#L2495
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