How do I get private data from the member functions? c++ - c++

Question

I am doing the Big c++ 2nd edition questions and I am on classes, I am stuck on a question. Basically I have to classes one called "person" and one called "Pemployee", I need to write the member functions of "Pemployee".
They gave me the declarations I need to implement the definitions.
What I don't get how to do is write call name, since it needs to call the private variable "person_data" which is a person object, I cannot access the string name directly but the member function of "person" has a "get_name" function which returns void, I dont understand how to get a string returned if I cannot return from the other definition.
Here are the two classes.
class Person
{
public:
Person();
Person(string pname, int page);
void get_name() const;
void get_age() const; //returns void
private:
string name;
int age; // 0 if unknown
};
class PEmployee
{
public:
PEmployee();
PEmployee(string employee_name, double initial_salary);
void set_salary(double new_salary);
double get_salary() const;
string get_name() const; //assuming I need to call person get_name
private:
Person person_data;
double salary;
};
So once again, how do I call the "Pemployee" get_name to return the string name of the person_data private variable

Answer 1

Typo in the book, Person::get_name should return string

Answer 2

A lot of programming books teach you to add get and set methods to your classes when the variable needs to be read or modified from outside of the class.
You need to create get methods for each of the private variables that your want value access to outside of the class.
You will need a set methods if you want to change the values from outside the class.
Example get method for your class
std::string get_name() const {return this->name;}

Answer 3

These signatures in the class called Person are pointless:
void get_name() const;
void get_age() const;
It is very probable that it is a typo. If it returned string then it whouldn't be pointless.
However if you would not like to change the functions signature or add a new memeber to the Person, then you should declare PEmployee as friend of Person, so member functions of PEmployee can reach private and protected members of Person. You can see below how to do this.
#include <string>
class PEmployee;
class Person
{
public:
friend PEmployee;
Person(){ }
Person(std::string pname, int page);
void get_name() const;
void get_age() const; //returns void
private:
std::string name;
int age; // 0 if unknown
};
class PEmployee
{
public:
PEmployee();
PEmployee(std::string employee_name, double initial_salary);
void set_salary(double new_salary);
double get_salary() const;
std::string get_name() const; //assuming I need to call person get_name
private:
Person person_data;
double salary;
};