Определение методов класса вне класса

#pragma once
#include <string>
#include <iostream>
 
using namespace std;
 
class publication
{
private:
    string name;
    mutable float price;
public:
    publication() :name("none"), price(0) { }
 
    publication(string name, float price) :name(name), price(price) { }
 
    inline void change()const;
    inline void put()const;
    void get();
};
 
inline void publication::change()const
{
    cout << "New price: ";
    cin >> price;
}
 
inline void publication::put()const
{
    cout << "Name: " << name << "|| Price: " << price << endl;
}
 
void publication::get()
{
    cout << "Name: ";
    cin >> name;
    cout << "Price: ";
    cin >> price;
}

#pragma once
#include <iostream>
#include "publication.h"
 
using namespace std;
 
class book : private publication
{
private:
    int size;
public:
    book() : publication(), size(0) { }
 
    book(string name, float price, int size) : publication(name, price), size(size) { }
 
    void change();
    void get();
    inline void put()const;
};
 
void book::change()
{
    publication::change();
}
 
void book::get()
{
    publication::get();
 
    cout << "Size: ";
    cin >> size;
}
 
inline void book::put()const
{
    publication::put();
 
    cout << "Size: " << size << endl;
}

#pragma once
#include <iostream>
#include "book.h"
 
using namespace std;
 
class type : private book
{
private:
    float time;
public:
    type() : book(), time(0) { }
 
    type(string name, float price, int size, float time) : book(name, price, size), time(time) { }
 
    inline void put()const;
    void change();
    void get();
};
 
inline void type::put()const
{
    book::put();
 
    cout << "Time: " << time;
}
 
void type::change()
{
    book::change();
 
    cout << "New time: ";
    cin >> time;
}
 
void type::get()
{
    book::get();
 
    cout << "Time: ";
    cin >> time;
}