import random

def generateCardId(length):
    """
    生成指定长度的随机卡号
    :param length: 卡号的长度
    :return: 生成的随机卡号
    """
    if length <= 0:
        raise ValueError("Length must be a positive integer.")

    # 初始化卡号
    card_id = ""
    # 数字范围
    numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

    # 生成随机卡号
    for _ in range(length):
        random_number = random.choice(numbers)
        card_id += str(random_number)

    return card_id

# 测试函数
if __name__ == "__main__":
    length = 18  # 指定卡号长度
    card_id = generateCardId(length)
    print(f"Generated Card ID: {card_id}")