设计一个用于人事管理的People类。考虑到通用性，可以只抽象出所有人员都 具有的属性：number(编号)，sex(性别) ，birthday(出生日期)，id(身份证号)等等。其中“出生日期”定义为一个“日期”类内嵌子对象。用成员函数实现对人员函数的录入和显示。要求包括：编写构造函数和析构函数、拷贝构造函数、内联成员函数，类的组合-People design a class for personnel management. Taking into account the generic and can only abstract all staff have the property: number (ID), sex (gender), birthday (date of birth), id (ID number), and so on. The　date of birth　is defined as a　date　class embedded child objects. Implemented by member functions of personnel entry and display functions. Requirements include: the preparation of a combination of constructor and destructor, copy constructor, inline member functions, class