題目：實現一個簡單的“銀行賬戶”類

要求：

1. 使用 元表 模擬面向對象。

2. 支持以下功能：

   • Account:new(owner, balance) 創建賬戶（初始余額可選，默認為 0）。

   • deposit(amount) 存款（不能為負數）。

   • withdraw(amount) 取款（余額不足時拒絕取款）。

   • getBalance() 查看余額。

3. 所有金額操作必須保留兩位小數（比如 100.567 存款后變成 100.57）。

4. 加分項：實現兩個賬戶之間的轉賬方法 transfer(toAccount, amount)。

local Account = {}
Account.__index = Accountlocal function RoundBalance(balance)return math.floor(balance * 100 + 0.5) / 100
endfunction Account:new(owner, balance)local obj = {owner = owner or "Alice",balance = (type(balance) == "number") and balance > 0 and RoundBalance(balance) or 0}setmetatable(obj, Account)return obj
endfunction Account:deposit(amount)if type(amount) == "number" and amount >= 0 thenself.balance = RoundBalance(self.balance + amount)print(tostring(self.owner) .. "存款")end
endfunction Account:withdraw(amount)if type(amount) == "number" and amount >= 0 and self.balance >= amount thenself.balance = RoundBalance(self.balance - amount)print(tostring(self.owner) .. "取款")end
endfunction Account:getBalance()return self.balance
endfunction Account:transfer(toAccount, amount)if type(toAccount) == "table" and type(amount) == "number" and amount >= 0 and self.balance >= amount then self.balance = RoundBalance(self.balance - amount)toAccount.balance = RoundBalance(toAccount.balance + amount)print("成功轉賬給" .. tostring(toAccount.owner) .. "：".. amount)end
endlocal a = Account:new("Alice", 100)
local b = Account:new("Bob")a:deposit(50.456)       -- Alice 存款
a:withdraw(30)          -- Alice 取款
a:transfer(b, 50)       -- 轉賬給 Bob
print("Alice 余額:", a:getBalance()) -- 70.46
print("Bob 余額:", b:getBalance())   -- 50.00