Create C++ source for an enum class with named numbers. 0 based.

numberwords-enum.cpp

#include <iostream>
#include <string>
#include <string_view>
#include <vector>
#include <sstream>
#include <array>
#include <cstdlib>

constexpr std::array ones {"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten"};
constexpr std::array teens {"eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"};
constexpr std::array tens {"", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"};

std::string num2words(int number)
{
	if (number == 0)
		return ones[0];

	std::ostringstream words;

	if (number >= 1000000)
	{
		words << num2words(number / 1000000) << "_million";
		if (number %= 1000000)
			words << '_';
	}

	if (number >= 1000)
	{
		words << num2words(number / 1000) << "_thousand";
		if (number %= 1000)
			words << '_';
	}

	if (number >= 100)
	{
		words << ones[number / 100] << "_hundred";
		if (number %= 100)
			words << '_';
	}

	if (number >= 20)
	{
		words << tens[number / 10];
		if (number %= 10)
			words << '_';
	}

	if (number > 10 && number < 20)
		words << teens[number - 11];
	else if (number > 0)
		words << ones[number];

	return words.str();
}

int main(int argc, char *argv[])
{
	const std::vector<std::string_view> args{argv, argv + argc};
	if (args.size() < 3)
	{
		std::cerr << "Usage: " << args[0] << " <classname> <count> [<prefix>]\n";
		return 1;
	}
	bool has_prefix { args.size() >= 4 };

	int number{};
	try
	{
		if ((number = std::stoi(args[2].data())) <= 0)
		{
			std::cerr << "<count=" << number << "> must be > 0\n";
			return 1;
		}
	}
	catch(const std::exception& e)
	{
		std::cerr << "exception: invalid count: " << e.what() << '(' << args[1] << ")\n";
		return 1;
	}

	std::cout << "enum class " << args[1] << "\n{\n   ";
	for (int ii{}; ii < number; ++ii)
	{
		if (ii)
		{
			std::cout << ", ";
			if (ii % 5 == 0)
				std::cout << "\n   ";
		}
		if (has_prefix)
			std::cout << args[3] << '_' << ii;
		else
			std::cout << num2words(ii);
	}
	std::cout << "\n};\n";
	return 0;
}

% ./numberwords-enum
Usage: ./numberwords-enum <classname> <count> [<prefix>]
% ./numberwords-enum "test : uint32_t" 100

enum class test : uint32_t
{
   zero, one, two, three, four,
   five, six, seven, eight, nine,
   ten, eleven, twelve, thirteen, fourteen,
   fifteen, sixteen, seventeen, eighteen, nineteen,
   twenty, twenty_one, twenty_two, twenty_three, twenty_four,
   twenty_five, twenty_six, twenty_seven, twenty_eight, twenty_nine,
   thirty, thirty_one, thirty_two, thirty_three, thirty_four,
   thirty_five, thirty_six, thirty_seven, thirty_eight, thirty_nine,
   forty, forty_one, forty_two, forty_three, forty_four,
   forty_five, forty_six, forty_seven, forty_eight, forty_nine,
   fifty, fifty_one, fifty_two, fifty_three, fifty_four,
   fifty_five, fifty_six, fifty_seven, fifty_eight, fifty_nine,
   sixty, sixty_one, sixty_two, sixty_three, sixty_four,
   sixty_five, sixty_six, sixty_seven, sixty_eight, sixty_nine,
   seventy, seventy_one, seventy_two, seventy_three, seventy_four,
   seventy_five, seventy_six, seventy_seven, seventy_eight, seventy_nine,
   eighty, eighty_one, eighty_two, eighty_three, eighty_four,
   eighty_five, eighty_six, eighty_seven, eighty_eight, eighty_nine,
   ninety, ninety_one, ninety_two, ninety_three, ninety_four,
   ninety_five, ninety_six, ninety_seven, ninety_eight, ninety_nine
};

% ./numberwords-enum test 20 blah

enum class test
{
   blah_0, blah_1, blah_2, blah_3, blah_4,
   blah_5, blah_6, blah_7, blah_8, blah_9,
   blah_10, blah_11, blah_12, blah_13, blah_14,
   blah_15, blah_16, blah_17, blah_18, blah_19
};