generated from mwc/problemset_numberwords
72 lines
2.0 KiB
Markdown
72 lines
2.0 KiB
Markdown
# Planning Number Words
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Before you start programming, do some planning here on how you will break down
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this problem. Here's a hint: if you start by writing functions for smaller numbers,
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you will find that these functions help you with the larger numbers. For each of
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the cases below, explain how you would turn a number into a string. Feel free to
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write in sentences or in pseudocode (pseudocode is a sort of "casual programming"
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where you're almost writing in code, being pretty specific without worrying about
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syntax. For each case below, assume the integer is zero or more--don't worry about
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negative integers.
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## Integers under 10
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(This one is done for you!)
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For an integer less than ten, you need to know the name of each digit, and look it
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up. You could use a big if/else statement like:
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```
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if number == 0:
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return "zero"
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elif number == 1:
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return "one"
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elif number == 1:
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return "two"
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if n < 10:
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return units[n]
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n % 10
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n% 100
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n % 1000
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```
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A cleaner way to do this would be to make a list of digit names, from zero to nine.
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Then you could just look up a digit's name:
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```
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digit_names = [
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"zero", "one", "two", "three", "four",
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"five", "six", "seven", "eight", "nine"
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]
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return digit_names[number]
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```
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## Integers under 20
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if n < 10:
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return units[n]
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## Integers under 100
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n < 100:
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return tens[n // 10] + ('' if n % 10 == 0 else '-' + units[n % 10])
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## Integers under 1000
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n < 1000:
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return units[n // 100] + ' hundred' + (' and ' + number_to_words(n % 100) if n % 100 != 0 else '')
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## Integers under 1000000
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n < 1000000:
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return (number_to_words(n // 1000) + ' thousand' +
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('' if n % 1000 == 0 else ' ' + number_to_words(n % 1000)))
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## Negative integers down to -1 million
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We won't deal with negative integers in this problem set,
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but how would you deal with a negative integer, using the
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functions above?
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if number < 0:
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return "negative " + int_under_1000000_to_str(-number)
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