Upside-down numbers: Difference between revisions

</pre>

=={{header|Julia}}==

<syntaxhighlight lang="julia">using Formatting

using ResumableFunctions

@resumable function gen_upsidedowns()

""" generate upside-down numbers (OEIS A299539) """

wrappings = [[1, 9], [2, 8], [3, 7], [4, 6],

[5, 5], [6, 4], [7, 3], [8, 2], [9, 1]]

evens = [19, 28, 37, 46, 55, 64, 73, 82, 91]

odds = [5]

ndigits, odd_index, even_index, olen, elen = 1, 0, 0, 1, 9

while true

if isodd(ndigits)

if olen > odd_index

@yield odds[begin + odd_index]

odd_index += 1

else

# build next odds, but switch to evens

odds = vec([hi * 10^(ndigits + 1) + 10 * i + lo for i in odds, (hi, lo) in wrappings])

ndigits += 1

odd_index = 0

olen = length(odds)

end

else

if elen > even_index

@yield evens[begin + even_index]

even_index += 1

else

# build next evens, but switch to odds

evens = vec([hi * 10^(ndigits + 1) + 10 * i + lo for i in evens, (hi, lo) in wrappings])

ndigits += 1

even_index = 0

elen = length(evens)

end

end

end

end

println("First fifty upside-downs:")

for (udcount, udnumber) in enumerate(gen_upsidedowns())

if udcount <= 50

print(lpad(udnumber, 5), udcount % 10 == 0 ? "\n" : "")

elseif udcount == 500

println("\nFive hundredth: ", format(udnumber, commas = true))

elseif udcount == 5000

println("Five thousandth: ", format(udnumber, commas = true))

elseif udcount == 50_000

println("Fifty thousandth: ", format(udnumber, commas = true))

elseif udcount == 500_000

println("Five hundred thousandth: ", format(udnumber, commas = true))

elseif udcount == 5_000_000

println("Five millionth: ", format(udnumber, commas = true))

break

end

end

</syntaxhighlight>{{out}}

<pre>

First fifty upside-downs:

5 19 28 37 46 55 64 73 82 91

159 258 357 456 555 654 753 852 951 1199

1289 1379 1469 1559 1649 1739 1829 1919 2198 2288

2378 2468 2558 2648 2738 2828 2918 3197 3287 3377

3467 3557 3647 3737 3827 3917 4196 4286 4376 4466

Five hundredth: 494,616

Five thousandth: 56,546,545

Fifty thousandth: 6,441,469,664

Five hundred thousandth: 729,664,644,183

Five millionth: 82,485,246,852,682