#include<iostream>
#include<cstring>
class student
{private:
std::string sname;
int grade;
public:
student():sname(0),grade(0){}
student(std::string name,int g=0)
{sname=name;
grade=g;
}
student(student &stu)
{sname=stu.getSname();
grade=stu.getGrade();
}//拷贝构造函数
std::string& getSname()
{return sname;}
int getGrade()
{return grade;}
student& operator=(student &stu)
{sname=stu.getSname();
grade=stu.getGrade();
return stu;
}
bool operator>(const student&);
bool operator<(const student&);
bool operator==(const student&);
bool operator!=(const student&);
void setGrade(int g)
{grade=g;}
void display();
void GradeTransition();//用于百分制到5分制的转换
~student(){}
};

bool student::operator>(const student &stu)
{if(this.grate>stu.getGrade())//当THIS对象的成绩大于STU的成绩时
{std::cout<<sname<<"成绩大于"<<stu.getSname();
return true;
}
else
{std::cout<<sname<<"成绩不大于"<<stu.getSname();
return false;}
}

bool student::operator<(const student &stu)
{if(this.grade<stu.getGrade())
{std::cout<<this.sname<<"成绩小于"<<stu.getSname();
return true;
}
else
{std::cout<<this.sname<<"成绩不小于"<<stu.getSname();
return false;
}
}

bool student::operator==(const student &stu)
{if(this.grade==getGrade())
{std::cout<<this.sname<<"成绩等于"<<stu.getSname();
return true;
}
else
{std::cout<<this.sname<<"成绩不等于"<<stu.getSname();
return false;
}

bool student::operator!=(const student &stu)
{if(this.grade!=stu.getGrade())
{std::cout<<this.sname<<"成绩不等于"<<stu.getSname();
return true;
}
else
return false;
}

void student::display()
{std::cout<<"姓名："<<this.sname<<std::endl;
std::cout<<"成绩："<<grade<<std::endl;
}

void student::GradeTransition()
{if(grate<=100&&grate>89)
{display();
std::cout<<"五分制成绩为："<<'A'<<std::endl;
}
else if(grate>79)
{{display();
std::cout<<"五分制成绩为："<<'B'<<std::endl;
}
else if(grate>69)
{{display();
std::cout<<"五分制成绩为："<<'C'<<std::endl;
}
else if(grate>59)
{{display();
std::cout<<"五分制成绩为："<<'D'<<std::endl;
}
else
{display();
std::cout<<"五分制成绩为："<<'E'<<std::endl;
}
}

int main()
{
student stu1(wang,80)
stu1.display();
stu1.GradeTransition();
student stu2(stu1);
stu2.display();
stu2.GradeTransition();
stu1.setGrade(59);
stu1.display();
stu1.GradeTransition();
stu2.display();
stu2.GradeTransition();

}



搞了一个下午都没搞好 希望能得到高手的帮助 谢谢

#include <iostream>
#include <cstdlib>
#include <string>
using namespace std;

class student
{
private:
    string sname;
    int grade;
public:
    student():sname(0),grade(0){}
    student(string name,int g=0)
    {
        sname=name;
        grade=g;
    }
    student(const student & stu)
    {
        sname=stu.sname;
        grade=stu.grade;
    }//¿½±´¹¹Ô캯Êý
    string & getSname()
    {
        return sname;
    }
    int getGrade(){return grade;}
    student & operator=(const student & stu)
    {
        sname=stu.sname;
        grade=stu.grade;
        return *this;
    }
    bool operator>(const student &);
    bool operator<(const student &);
    bool operator==(const student &);
    bool operator!=(const student &);
    void setGrade(int g){grade=g;}
    void display();
    void GradeTransition();//ÓÃÓÚ°Ù·ÖÖƵ½5·ÖÖƵÄת»»
    ~student(){}
};

bool student::operator>(const student & stu)
{
    if(grade>stu.grade)//µ±THIS¶ÔÏóµÄ³É¼¨´óÓÚSTUµÄ³É¼¨Ê±
    {
        cout<<sname<<\"³É¼¨´óÓÚ\"<<stu.sname;
        return true;
    }
    else
    {
        cout<<sname<<\"³É¼¨²»´óÓÚ\"<<stu.sname;
        return false;
    }
}

bool student::operator<(const student & stu)
{
    if(grade<stu.grade)
    {
        cout<<sname<<\"³É¼¨Ð¡ÓÚ\"<<stu.sname;
        return true;
    }
    else
    {
        cout<<sname<<\"³É¼¨²»Ð¡ÓÚ\"<<stu.sname;
        return false;
    }
}

bool student::operator==(const student & stu)
{
    if(grade==stu.grade)
    {
        cout<<sname<<\"³É¼¨µÈÓÚ\"<<stu.sname;
        return true;
    }
    else
    {
        cout<<sname<<\"³É¼¨²»µÈÓÚ\"<<stu.sname;
        return false;
    }
}

bool student::operator!=(const student & stu)
{
    if(grade!=stu.grade)
    {
        cout<<sname<<\"³É¼¨²»µÈÓÚ\"<<stu.sname;
        return true;
    }
    else
        return false;
}

void student::display()
{
    cout<<\"ÐÕÃû£º\"<<sname<<endl;
    cout<<\"³É¼¨£º\"<<grade<<endl;
}

void student::GradeTransition()
{
    display();
    if(grade<=100 && grade>89)
    {
        cout<<\"Îå·ÖÖƳɼ¨Îª£º\"<<'A'<<endl;
    }
    else if(grade>79)
    {
        cout<<\"Îå·ÖÖƳɼ¨Îª£º\"<<'B'<<endl;
    }
    else if(grade>69)
    {
        cout<<\"Îå·ÖÖƳɼ¨Îª£º\"<<'C'<<endl;
    }
    else if(grade>59)
    {
        cout<<\"Îå·ÖÖƳɼ¨Îª£º\"<<'D'<<endl;
    }
    else
    {
        cout<<\"Îå·ÖÖƳɼ¨Îª£º\"<<'E'<<endl;
    }
}

int main()
{
    student stu1(\"wang\",80);
    stu1.display();
    stu1.GradeTransition();
    student stu2(stu1);
    stu2.display();
    stu2.GradeTransition();
    stu1.setGrade(59);
    stu1.display();
    stu1.GradeTransition();
    stu2.display();
    stu2.GradeTransition();

    system(\"pause\");
    return 0;
}