继承与派生

求教高手啊，继承不是不能继承基类的构造函数吗？？？可是我的程序竟然继承啦？？？求解啊
#include<iostream.h>
#include<string.h>

//基类person
class person
{
protected:
    char name[10];
    char sex[4];
    int age;
public:
    person(){}
    ~person(){}
    void show(){}
};





//派生student类
class student:virtual public person
{
protected:
    char speciality[10];  //学生的专业
    int num;             //学生的学号
public:
    student();
    ~student();
    void show();
};

//student类构造函数的实现
student::student()
{
    cout<<"请输入学生的信息:"<<endl;
    cout<<"学号:";
    cin>>num;
    cout<<"姓名:";
    cin>>name;
    cout<<"性别:";
    cin>>sex;
    cout<<"年龄:";
    cin>>age;
    cout<<"专业:";
    cin>>speciality;
}

//析构函数
student::~student()
{
}

//显示函数的实现
void student::show()
{
    cout<<"学生的信息如下:"<<endl;
    cout<<"学号"<<"   "<<"姓名"<<"   "<<"性别"<<"   "<<"年龄"<<"   "<<"专业"<<endl;
    cout<<num<<"   "<<name<<"   "<<sex<<"   "<<age<<"   "<<speciality<<endl;
}








//teacher类
class teacher:virtual public person
{
protected :
     char department[20];
public:
    teacher();
    ~teacher();
    void show();
};

//teacher类构造函数的实现
teacher::teacher()
{
    cout<<"请输入老师的信息:"<<endl;
    cout<<"姓名:";
    cin>>name;
    cout<<"性别:";
    cin>>sex;
    cout<<"年龄:";
    cin>>age;
    cout<<"院系:";
    cin>>department;
}


//析构函数的实现
teacher::~teacher()
{
}

//显示函数的实现
void teacher::show()
{
    cout<<"老师的信息如下:"<<endl;
    cout<<"姓名"<<"   "<<"性别"<<"   "<<"年龄"<<"   "<<"院系"<<endl;
    cout<<name<<"   "<<sex<<"   "<<age<<"   "<<department<<endl;
}







//派生类stuteacher
class  stuteacher: public student, public teacher
{
public:
    stuteacher();
    ~stuteacher();
    void show();
};

//stuteacher类构造函数的实现
stuteacher::stuteacher()
{
    cout<<"请输入在读老师的信息:"<<endl;
    cout<<"姓名:";
    cin>>name;
    cout<<"性别:";
    cin>>sex;
    cout<<"年龄:";
    cin>>age;
    cout<<"院系:";
    cin>>department;
    cout<<"专业";
    cin>>speciality;
}


//析构函数的实现
stuteacher::~stuteacher()
{
}


//stuteacher类显示函数的实现
void stuteacher::show()
{
    cout<<"老师的信息如下:"<<endl;
    cout<<"姓名"<<"   "<<"性别"<<"   "<<"年龄"<<"   "<<"院系"<<"   "<<"专业"<<endl;
    cout<<name<<"   "<<sex<<"   "<<age<<"   "<<department<<"   "<<speciality<<endl;
}



void main()
{
    student objs;
    objs.show();
    teacher objt;
    objt.show();
    stuteacher objst;
    objst.show();
}