student.h程序

#ifndef _STUDENT_H_
#define _STUDENT_H_
#include <string>
using namespace std;
class CStudent
{
private:
    string strName ;
    double chinese ;
    double math;
    double english;
public:
    CStudent();
    CStudent(string Name,double c,double m,double e);
    CStudent operator+(CStudent S);
    friend ostream& operator<<(ostream& out , CStudent S);
    void SetChinese(double a);
    void SetMath(double a);
    void SetEnglish(double a);
    string returnName();
    double returnChinese();
    double returnMath();
    double returnEnglish();
    double returnTotalPreformance();
    double returnAverage();
    ~CStudent(){}
};
#endif






主程序



#include <iostream>
#include "student.h"
using namespace std;
int main()
{   
    CStudent student1("XiaoMing",50,80,98);
    CStudent student2("XiaoHua",70,78,68);
    CStudent student3("NingJian",86,78,83);
    //  1、读取某同学单科分数
    cout<<student1<<endl;
    cout<<student2<<endl;
    cout<<student3<<endl;
    //  2、重新设置分数
    student1.SetChinese(56);
    student2.SetEnglish(87);
    student3.SetMath(87);
    //  3、计算不同学生同学科的总成绩
    CStudent General ;
    General = student1+student2+student3;
    cout<<General;
    //  4、查看多个人的各科目平均成绩
    cout<<"Average of Chinese :"<<General.returnChinese()/3
        <<"\nAverage of Math :"<<General.returnMath()/3
        <<"\nAverage of English :"<<General.returnEnglish()/3<<endl;
    //  5、查看个人平均成绩
    cout<<"Average of students : \n";
    cout<<student1.returnName()<<" : "<<student1.returnAverage()<<endl;
    cout<<student2.returnName()<<" : "<<student2.returnAverage()<<endl;
    cout<<student3.returnName()<<" : "<<student3.returnAverage()<<endl;
    //  6、查看个人总成绩
    cout<<"Total of students : \n";
    cout<<student1.returnName()<<" : "<<student1.returnTotalPreformance()<<endl;
    cout<<student2.returnName()<<" : "<<student2.returnTotalPreformance()<<endl;
    cout<<student3.returnName()<<" : "<<student3.returnTotalPreformance()<<endl;
    cin.get();
    return 0 ;
}





头文件中student.cpp程序



#include <iostream>
#include "student.h"
using namespace std;
CStudent::CStudent()
{
    strName = "General Student";
    chinese = 0 ;
    math = 0 ;
    english = 0 ;
}
CStudent::CStudent(std::string Name, double c, double m, double e)
{
    strName = Name ;
    chinese = c ;
    math = m ;
    english = e ;
}
CStudent CStudent::operator +(CStudent S)
{
    CStudent temp ;
    temp.strName = "Total Preformance";
    temp.chinese = this->chinese + S.chinese;
    temp.math = this->math + S.math ;
    temp.english = this->english + S.english;
    return temp;
}
ostream& operator <<(ostream& out ,  CStudent S)
{
    out<<S.strName<<"( "<<S.chinese<<" , "<<S.math<<" , "<<S.english<<" )"<<endl;
    return out;
}
void CStudent::SetChinese(double a)
{
    chinese = a;
}
void CStudent::SetEnglish(double a)
{
    english = a;
}
void CStudent::SetMath(double a)
{
    math = a;
}
double CStudent::returnChinese()
{
    return chinese ;
}
double CStudent::returnEnglish()
{
    return english ;
}
double CStudent::returnMath()
{
    return math ;
}
double CStudent::returnTotalPreformance()
{
    return chinese + math + english ;
}
double CStudent::returnAverage()
{
    return (chinese + math + english)/3;
}
string CStudent::returnName()
{
    return strName;
}


程序运行后出现错误

D:\网上下载的vc++（1月29日）\MSDev98\MyProjects\重复\student.cpp(29) : error C2248: 'strName' : cannot access private member declared in class 'CStudent'
        d:\网上下载的vc++（1月29日）\msdev98\myprojects\重复\student.h(8) : see declaration of 'strName'
D:\网上下载的vc++（1月29日）\MSDev98\MyProjects\重复\student.cpp(29) : error C2248: 'chinese' : cannot access private member declared in class 'CStudent'
        d:\网上下载的vc++（1月29日）\msdev98\myprojects\重复\student.h(9) : see declaration of 'chinese'
D:\网上下载的vc++（1月29日）\MSDev98\MyProjects\重复\student.cpp(29) : error C2248: 'math' : cannot access private member declared in class 'CStudent'
        d:\网上下载的vc++（1月29日）\msdev98\myprojects\重复\student.h(10) : see declaration of 'math'
D:\网上下载的vc++（1月29日）\MSDev98\MyProjects\重复\student.cpp(29) : error C2248: 'english' : cannot access private member declared in class 'CStudent'
        d:\网上下载的vc++（1月29日）\msdev98\myprojects\重复\student.h(11) : see declaration of 'english'
Error executing cl.exe.


为什么会出现不能访问类的私有变量呢？


我是初学者，照书上写的程序，可运行不出来，希望各位高手帮忙，谢啦