题解 | #学英语#

lst = [
    'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten',
    'eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen',
    'eighteen', 'nineteen'
]

dic = {
    2 : 'twenty', 3 : 'thirty', 4 : 'forty', 5 : 'fifty', 6 : 'sixty',
    7 : 'seventy', 8 : 'eighty', 9 : 'ninety'
}

def eng(n):
    if n < 20:
        return lst[n - 1]
    else:
        if n % 10 == 0:
            return dic[n // 10]
        else:
            return dic[n // 10] + ' ' + lst[n % 10 - 1]

while True:
    try:
        s = input()
        if not s.isdigit():
            print('error')
            continue
        sgood = ''
        for i, c in enumerate(s[::-1]):
            sgood += c
            if (i + 1) % 3 == 0:
                sgood += ','
        sgood = sgood[::-1]
        nums = sgood.split(',')
        for i, n in enumerate(nums):
            if not n:
                continue
            if len(n) == 3:
                if n[0] != '0':
                    print(eng(int(n[0])), 'hundred', end=' ')
                    if int(n[1:]) > 0:
                        print('and', end=' ')
                        print(eng(int(n[1:])), end=' ')
                else:
                    print(eng(int(n)), end=' ')
            else:
                print(eng(int(n)), end=' ')
            # 单位判断
            if len(nums[i:]) == 4:
                print('billion', end=' ')
            elif len(nums[i:]) == 3:
                print('million', end=' ')
            elif len(nums[i:]) == 2:
                print('thousand', end=' ')
        print()
    except:
        break