#include<iostream.h>
#include<string>
class Student{
private:
    string name, num;
    float c,m,e;
public:
    Student();//定义无参版本的构造函数
    Student(string na,string nu,float m1,float c1,float e1);//定义有参版本的构造函数
    ~Student()//定义析构函数
    void showStudent();
};
    Student::Student()
    {name="刘洋";
    num=12;
    m=0;
    c=0;
    e=0;
    }//在构造函数中对私有成员赋值
    Student::~Student()
    {cout<<"析构"<<num<<endl;
    }

    Student::Student(string na,string nu,float m1,float c1,float e1);//定义有参版本的构造函
    {name=na;
    num=nu;
    m=m1;
    c=c1;
    e=e1;
    }//在构造函数中对私有成员赋值
    Student::~student()
    {cout<<"析构"<<num<<endl;
    }
    inline void Student::showStudent()
    {cout<<name<<num<<m<<c<<e<<endl;
    }
};
int main()
{
   
    Student A,B;
    A.showStudent();
    B.showStudent("刘洋","12",95,100,78);
    return 0;

#include<iostream>
#include<string>
using namespace std;
class Student{
private:
    string name;int num;
    float c,n,e;
public:
    Student();//声明无参版本的构造函数
    Student(string na,int nu,float n1,float c1,float e1);//声明有参版本的构造函数
    ~Student();
    void showStudent();
    float avar();
};
Student::Student()
{name="刘奎";
num=90;
n=0;
c=0;
e=0;
cout<<"构造"<<name<<endl;
}


Student::Student(string na,int nu,float n1,float c1,float e1)//定义有参版本的构造函
{name=na;
num=nu;
n=n1;
c=c1;
e=e1;
cout<<"构造"<<name<<endl;
}
Student::~Student()
{cout<<"析构:"<<name<<endl;
}
float Student::avar()
{return (n+c+e)/3;}
void Student::showStudent()
{cout<<"name"<<" "<<"num"<<" "<<"n"<<" "<<"c"<<" "<<"e"<<endl;
cout<<name<<" "<<num<<" "<<n<<" "<<c<<" "<<e<<endl;
}

int main()
{
    Student stu1;   
    stu1.showStudent();
    Student stu2("刘洋",12,95,100,78);
    stu2.showStudent();
    cout<<"stu1的信息:"<<stu1.avar()<<endl;
    cout<<"stu2的信息:"<<stu2.avar()<<endl;
    return 0;
}

楼上的谢谢你，你的楼上是我自己写的程序！和你的应该差不多!