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//
// "Elephants walking
// Along the trails
//
// Are holding hands
// By holding tails."
//
// from Holding Hands
// by Lenore M. Link
//
const std = @import("std");
const Elephant = struct {
letter: u8,
tail: *Elephant = undefined,
visited: bool = false,
};
pub fn main() void {
var elephantA = Elephant{ .letter = 'A' };
// (Please add Elephant B here!)
var elephantB = Elephant{ .letter = 'B' };
var elephantC = Elephant{ .letter = 'C' };
// Link the elephants so that each tail "points" to the next elephant.
// They make a circle: A->B->C->A...
elephantA.tail = &elephantB;
// (Please link Elephant B's tail to Elephant C here!)
elephantB.tail = &elephantC;
elephantC.tail = &elephantA;
visitElephants(&elephantA);
std.debug.print("\n", .{});
}
// This function visits all elephants once, starting with the
// first elephant and following the tails to the next elephant.
// If we did not "mark" the elephants as visited (by setting
// visited=true), then this would loop infinitely!
fn visitElephants(first_elephant: *Elephant) void {
var e = first_elephant;
while (!e.visited) {
std.debug.print("Elephant {u}. ", .{e.letter});
e.visited = true;
e = e.tail;
}
}
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