定义一个类实现银行帐户的概念，包括的变量有“帐号”和“存款余额”，包括的方法有“存款”、“取款”和“查询余额”。定义主类，创建帐户类的对象，并完成相应操作。-Define a class implements the concept of bank accounts, including the variable of " account"　and " deposits" , including the method of " deposits" , " withdrawals"　and " query the balance."　Define the main class, the class object to create an account and complete the corresponding operation.