tasks a-s

Task/Number-names/Lua/number-names.lua

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+words = {"one ", "two ", "three ", "four ", "five ", "six ", "seven ", "eight ", "nine "}
+levels = {"thousand ", "million ", "billion ", "trillion ", "quadrillion ", "quintillion ", "sextillion ", "septillion ", "octillion ", [0] = ""}
+iwords = {"ten ", "twenty ", "thirty ", "forty ", "fifty ", "sixty ", "seventy ", "eighty ", "ninety "}
+twords = {"eleven ", "twelve ", "thirteen ", "fourteen ", "fifteen ", "sixteen ", "seventeen ", "eighteen ", "nineteen "}
+
+function digits(n)
+  local i, ret = -1
+  return function()
+    i, ret = i + 1, n % 10
+	if n > 0 then
+      n = math.floor(n / 10)
+	  return i, ret
+	end
+  end
+end
+
+level = false
+function getname(pos, dig) --stateful, but effective.
+  level = level or pos % 3 == 0
+  if(dig == 0) then return "" end
+  local name = (pos % 3 == 1 and iwords[dig] or words[dig]) .. (pos % 3 == 2 and "hundred " or "")
+  if(level) then name, level = name .. levels[math.floor(pos / 3)], false end
+  return name
+end
+
+local val, vword = io.read() + 0, ""
+
+for i, v in digits(val) do
+  vword = getname(i, v) .. vword
+end
+
+for i, v in ipairs(words) do
+  vword = vword:gsub("ty " .. v, "ty-" .. v)
+  vword = vword:gsub("ten " .. v, twords[i])
+end
+
+if #vword == 0 then print "zero" else print(vword) end