C++ 继承函数

#include <iostream>
using namespace std;

class  passport
{
public:
    passport() //默认构造
    {
 　　
    }
    passport(int id,string tongxingzheng,string mima,string shenfen) 
    {
        this->id = id;
        this->pass = tongxingzheng;
        this->password = mima;
        this->shenfenzheng = shenfen;
    }
    ~passport()//析构
    {
    }
 protected: 
     //定义父类成员变量
    int  id;
    string pass;
    string password;
    string shenfenzheng;
    
};

class xiaoming :public passport  //子类继承父类passport的成员
{
public:
    xiaoming(int id, string tongxingzheng, string mima, string shenfen)
    {
        this->id = id;
        this->pass = tongxingzheng;
        this->password = mima;
        this->shenfenzheng = shenfen;
    }

};


int main()
{    
    passport xiaoxiao(1,"xiaoxiao", "123456", "123456789");
    xiaoming xiaoqi(2, "xiaoqi", "123456", "987654321");
    return 0;

}