#include <fcntl.h>

 #include <iostream>

 #include <cstring>

 #include <cstdlib>

 #include <unistd.h>

 using namespace std;

 class Human{

 private:

     virtual void give_shell(){

         system("/bin/sh");

     }

 protected:

     int age;

     string name;

 public:

     virtual void introduce(){

         cout << "My name is " << name << endl;

         cout << "I am " << age << " years old" << endl;

     }

 };

 class Man: public Human{

 public:

     Man(string name, int age){

         this->name = name;

         this->age = age;

         }

         virtual void introduce(){

         Human::introduce();

                 cout << "I am a nice guy!" << endl;

         }

 };

 class Woman: public Human{

 public:

         Woman(string name, int age){

                 this->name = name;

                 this->age = age;

         }

         virtual void introduce(){

                 Human::introduce();

                 cout << "I am a cute girl!" << endl;

         }

 };

 int main(int argc, char* argv[]){

     Human* m = new Man("Jack", );

     Human* w = new Woman("Jill", );

     size_t len;

     char* data;

     unsigned int op;

     while(){

         cout << "1. use\n2. after\n3. free\n";

         cin >> op;

         switch(op){

             case :

                 m->introduce();

                 w->introduce();

                 break;

             case :

                 len = atoi(argv[]);

                 data = new char[len];

                 read(open(argv[], O_RDONLY), data, len);

                 cout << "your data is allocated" << endl;

                 break;

             case :

                 delete m;

                 delete w;

                 break;

             default:

                 break;

         }

     }

     return ;

 }