按照1美元等于6人民币汇率编写一个美元和人民币的双向兑换程序

按照1美元等于6人民币的固定汇率，我们可以创建一个简单的Python函数来进行双向兑换：

def currency_converter(amount, from_currency="USD", to_currency="CNY"):
    # 定义汇率
    rate = {
        "USD": 6,  # 美元对人民币
        "CNY": 1 / 6,  # 人民币对美元
    }

    # 检查输入货币是否有效
    if from_currency not in rate or to_currency not in rate:
        return "无效的货币类型"

    # 进行转换
    converted_amount = amount * rate[from_currency]

    # 根据目标货币返回结果
    if to_currency == "USD":
        return f"{amount} {from_currency} = {converted_amount:.2f} {to_currency}"
    else:
        return f"{amount} {from_currency} = {converted_amount:.2f} {to_currency}"

# 示例
print(currency_converter(100, "USD"))  # 输出：100 USD = 600.00 CNY
print(currency_converter(600, "CNY", "USD"))  # 输出：600.00 CNY = 100.00 USD