建立一个电费管理系统要求该系统具有以下功能：

1.自动计算电费

2.按照电费的高低进行排序

3.查询用户的电费情况

4.增添用户

5.删除用户-The establishment of an electricity management system requirements for the system has the following features: 1. Automatically calculate tariff 2. In accordance with the level of electricity tariffs sort 3. Inquiries electricity users 4. Add users 5. Delete User