面向对象设计C---静态成员变量 实验（二十五）

#include <iostream>
#include <cstring>  //在 vc6.0 下 使用#include<string.h>
           //在 g++ 环境 为 cstring

using namespace std;
class CStudent
{
  public:
    CStudent();//构造函数 没有返回值
    CStudent(char *name,int age); //定义一个带参 构造函数
    ~CStudent();         //析构函数，唯一，不能重载
    CStudent(const CStudent &student);

    friend class CTeacher;

    CStudent &init(char *name,int age);         //赋值功能
    void add(int age);  //对静态成员变量操作
    void  output();            //输出类对象的两个数据成员
  private:
    char name[20];
    static int  age;   //静态成员变量 在类中声明
};

int CStudent::age=0;          //在 类外 定义

CStudent::CStudent()  //无参构造函数
{
    strcpy(this->name," ");
    this->age=0;
}

CStudent::CStudent(char *name,int age)  //带参 构造函数实现
{
    strcpy(this->name,name);
    this->age=age;
}

CStudent::CStudent(const CStudent &student)
{
    strcpy(this->name,student.name);
    this->age = student.age;
}

CStudent::~CStudent()
{
    cout<<"the object is deconstructing..."<<endl;
}

CStudent &CStudent::init(char *name,int age)
{
    strcpy(this->name,name);
    this->age=age;
    return (*this);
}
void CStudent::add(int age)
{
    CStudent::age += 10;
}
void CStudent::output()
{
    cout<<this->name<<"      "<<this->age<<endl;
}

/*--------------------------------------------------*/
class CTeacher
{
public:
    CStudent &visit(CStudent &student,char *name,int age);
};

CStudent &CTeacher::visit(CStudent &student,char *name,int age)
{
    strcpy(student.name,name);
    student.age = age;
    return student;
}
/*--------------------------------------------------*/

int main()
{
    CStudent stu1;
    CTeacher teacher1;
    teacher1.visit(stu1,"tom",23);
    stu1.add(10);        //静态成员变量age +10
    stu1.output();    //23+10=33

    CStudent stu2;  //stu1 stu2 共享静态 age
    stu2.add(15);     //33+15=48 共享的成语变量
    stu2.output();   // stu2 的 name 初始化是 空串

    return 0;
}

ywx@yuweixian:~/yu/c++/shiyan1$ ./student2
tom      33
       10    这里name 初始化为 空串
the object is deconstructing...
the object is deconstructing...
ywx@yuweixian:~/yu/c++/shiyan1$