using System;
using System.Collections.Generic;

foreach (var (disk, fromPeg, toPeg) in Hanoi(3, 'A', 'C', 'B'))
{
    Console.WriteLine($"Move disk {disk} from {fromPeg} to {toPeg}");
}

// An iterator: each move is produced only when the loop above asks for the next one.
static IEnumerable<(int Disk, char From, char To)> Hanoi(int n, char source, char target, char spare)
{
    if (n == 0)
    {
        yield break;
    }
    foreach (var move in Hanoi(n - 1, source, spare, target))
    {
        yield return move;
    }
    yield return (n, source, target);
    foreach (var move in Hanoi(n - 1, spare, target, source))
    {
        yield return move;
    }
}