IndexError:列表索引超出范围:尝试将数字显示为英文单词时

def number_to_words(num):
    ones = ["", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"]
    tens = ["", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]
    
    if num < 10:
        return ones[num]
    elif num < 100:
        return tens[num // 10] + ("-" + ones[num % 10] if num % 10 != 0 else "")
    else:
        raise NotImplementedError("Only numbers up to 99 are supported")

# 错误的调用示例
print(number_to_words(101))  # 这将引发 IndexError

def number_to_words(num):
    ones = ["", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"]
    tens = ["", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]
    
    if num < 0 or num > 99:
        raise ValueError("Number must be between 0 and 99")
    
    if num < 10:
        return ones[num]
    elif num < 100:
        return tens[num // 10] + ("-" + ones[num % 10] if num % 10 != 0 else "")

# 正确的调用示例
try:
    print(number_to_words(101))  # 这将引发 ValueError
except ValueError as e:
    print(e)