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# Convert integer to English [FINALIZED]

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Given a non-negative integer up to $999\,999\,999$, write it in English.

The input number can be in any form other than English (though you'll typically want to use the native integer type of your language).

When there are several variants of writing the number in English, you can choose whichever suits you more. For example, the input $120$ may give the output one hundred twenty or one hundred and twenty.

The numbers must be formatted as follows:

• Two-digit numbers must be written with dashes where applicable e.g. twenty-five, not twenty five.

• powers of ten start with “one”, e.g. one hundred, not just hundred.

• The tens/ones part, if not zero, must be separated from the hundreds part with and, e.g. two hundred and five, not two hundred five.

• The above rules are applied also to the factors of thousand and million.

• moreover the global tens/ones part has bto be separated by and whenever anything larger is present, even if the hundreds part is missing.

• Adjacent words must be separated by a single space, or a single dash without space where applicable.

• Leading and/or trailing spaces are not allowed. However, if the result is printed, a single trailing newline (not preceded by any spaces) is allowed.

Ungolfed reference implementation

Test cases:

        0 zero
1 one
4 four
10 ten
16 sixteen
42 forty-two
125 one hundred and twenty-five
1024 one thousand and twenty-four
1100 one thousand one hundred
12345 twelve thousand three hundred and forty-five
1000000 one million
1000001 one million and one
7023000 seven million twenty-three thousand
11012021 eleven million twelve thousand and twenty-one
999999999 nine hundred and ninety-nine million nine hundred and ninety-nine thousand nine hundred and ninety-nine

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Reference implementation is incorrect (5 comments)