面向对象设计C---友元函数实验（二十一）

#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 CStudent &input(CStudent &stu,char *name,int age);

    CStudent &init(char *name,int age);         //赋值功能
    void  output();            //输出类对象的两个数据成员
  private:
    char name[20];
    int  age;
};

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::output()
{
    cout<<this->name<<"      "<<this->age<<endl;
}

CStudent &input(CStudent &stu,char *name,int age)  这里都是 引用，如果不用 & ，就要进行数据拷贝
      返回一个新的对象，
{
    strcpy(stu.name,name);
    stu.age = age;
    return stu;
}
int main()
{
    CStudent stu1("jim",22);
    stu1.output();
    input(stu1,"marry",21);
    stu1.output();
    return 0;
}

ywx@yuweixian:~/yu/c++/shiyan1$ ./student1
jim      22
marry      21
the object is deconstructing...
ywx@yuweixian:~/yu/c++/shiyan1$