Task: Spelling of ordinal numbers


C++: #include <iostream>
#include <string>
#include <cstdint>

typedef std::uint64_t integer;

struct number_names {
    const char* cardinal;
    const char* ordinal;
};

const number_names small[] = {
    { "zero", "zeroth" }, { "one", "first" }, { "two", "second" },
    { "three", "third" }, { "four", "fourth" }, { "five", "fifth" },
    { "six", "sixth" }, { "seven", "seventh" }, { "eight", "eighth" },
    { "nine", "ninth" }, { "ten", "tenth" }, { "eleven", "eleventh" },
    { "twelve", "twelfth" }, { "thirteen", "thirteenth" },
    { "fourteen", "fourteenth" }, { "fifteen", "fifteenth" },
    { "sixteen", "sixteenth" }, { "seventeen", "seventeenth" },
    { "eighteen", "eighteenth" }, { "nineteen", "nineteenth" }
};

const number_names tens[] = {
    { "twenty", "twentieth" }, { "thirty", "thirtieth" },
    { "forty", "fortieth" }, { "fifty", "fiftieth" },
    { "sixty", "sixtieth" }, { "seventy", "seventieth" },
    { "eighty", "eightieth" }, { "ninety", "ninetieth" }
};

struct named_number {
    const char* cardinal;
    const char* ordinal;
    integer number;
};

const named_number named_numbers[] = {
    { "hundred", "hundredth", 100 },
    { "thousand", "thousandth", 1000 },
    { "million", "millionth", 1000000 },
    { "billion", "billionth", 1000000000 },
    { "trillion", "trillionth", 1000000000000 },
    { "quadrillion", "quadrillionth", 1000000000000000ULL },
    { "quintillion", "quintillionth", 1000000000000000000ULL }
};

const char* get_name(const number_names& n, bool ordinal) {
    return ordinal ? n.ordinal : n.cardinal;
}

const char* get_name(const named_number& n, bool ordinal) {
    return ordinal ? n.ordinal : n.cardinal;
}

const named_number& get_named_number(integer n) {
    constexpr size_t names_len = std::size(named_numbers);
    for (size_t i = 0; i + 1 < names_len; ++i) {
        if (n < named_numbers[i + 1].number)
            return named_numbers[i];
    }
    return named_numbers[names_len - 1];
}

std::string number_name(integer n, bool ordinal) {
    std::string result;
    if (n < 20)
        result = get_name(small[n], ordinal);
    else if (n < 100) {
        if (n % 10 == 0) {
            result = get_name(tens[n/10 - 2], ordinal);
        } else {
            result = get_name(tens[n/10 - 2], false);
            result += "-";
            result += get_name(small[n % 10], ordinal);
        }
    } else {
        const named_number& num = get_named_number(n);
        integer p = num.number;
        result = number_name(n/p, false);
        result += " ";
        if (n % p == 0) {
            result += get_name(num, ordinal);
        } else {
            result += get_name(num, false);
            result += " ";
            result += number_name(n % p, ordinal);
        }
    }
    return result;
}

void test_ordinal(integer n) {
    std::cout << n << ": " << number_name(n, true) << '\n';
}

int main() {
    test_ordinal(1);
    test_ordinal(2);
    test_ordinal(3);
    test_ordinal(4);
    test_ordinal(5);
    test_ordinal(11);
    test_ordinal(15);
    test_ordinal(21);
    test_ordinal(42);
    test_ordinal(65);
    test_ordinal(98);
    test_ordinal(100);
    test_ordinal(101);
    test_ordinal(272);
    test_ordinal(300);
    test_ordinal(750);
    test_ordinal(23456);
    test_ordinal(7891233);
    test_ordinal(8007006005004003LL);
    return 0;
}



Go: import (
	"fmt"
	"strings"
)

func main() {
	for _, n := range []int64{
		1, 2, 3, 4, 5, 11, 65, 100, 101, 272, 23456, 8007006005004003,
	} {
		fmt.Println(sayOrdinal(n))
	}
}

var irregularOrdinals = map[string]string{
	"one":    "first",
	"two":    "second",
	"three":  "third",
	"five":   "fifth",
	"eight":  "eighth",
	"nine":   "ninth",
	"twelve": "twelfth",
}

func sayOrdinal(n int64) string {
	s := say(n)
	i := strings.LastIndexAny(s, " -")
	i++
	
	
	
	
	if x, ok := irregularOrdinals[s[i:]]; ok {
		s = s[:i] + x
	} else if s[len(s)-1] == 'y' {
		s = s[:i] + s[i:len(s)-1] + "ieth"
	} else {
		s = s[:i] + s[i:] + "th"
	}
	return s
}



var small = [...]string{"zero", "one", "two", "three", "four", "five", "six",
	"seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen",
	"fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"}
var tens = [...]string{"", "", "twenty", "thirty", "forty",
	"fifty", "sixty", "seventy", "eighty", "ninety"}
var illions = [...]string{"", " thousand", " million", " billion",
	" trillion", " quadrillion", " quintillion"}

func say(n int64) string {
	var t string
	if n < 0 {
		t = "negative "
		
		n = -n
	}
	switch {
	case n < 20:
		t += small[n]
	case n < 100:
		t += tens[n/10]
		s := n % 10
		if s > 0 {
			t += "-" + small[s]
		}
	case n < 1000:
		t += small[n/100] + " hundred"
		s := n % 100
		if s > 0 {
			t += " " + say(s)
		}
	default:
		
		sx := ""
		for i := 0; n > 0; i++ {
			p := n % 1000
			n /= 1000
			if p > 0 {
				ix := say(p) + illions[i]
				if sx != "" {
					ix += " " + sx
				}
				sx = ix
			}
		}
		t += sx
	}
	return t
}