When you make a class the friend of another class, is it required to use a prototype to access its members?

[SomeAmazingGuy]

When a class has been declared as a friend in another class, does the friend class have to have a prototype in order for the other class to use to access its private and public members?

Please see below to understand what I mean

The Plants class has access to the private members in Color class. But is it required to use a prototype (that was declared in the Colors class) and define it in the plants class in order to access the members in Colors?

//Plants class
#include <iostream>
#include "Color.cpp"

using namespace std;


class Plants
{
    string plantName;
    friend class Color;        //Color class is now a friend of plants class

public:

}object;

void Color::setMembers ()    //defining function that was declared by the prototype in color class
{
    black = "idc what you say, black is a color";
    cout << black;
}


int main ()
{
    object1.setMembers ();
}

//Color class
#include <iostream>
#ifndef COLOR_CPP
#define COLOR_CPP

using namespace std;

class Plants;

class Color
{
    string black;
	string white;

public:

	void setMembers ();        //do I have to use a prototype declared here in order for the plants class to access the private members in color?

}object1;




#endif

[Peter87]

The Plants class has access to the private members in Color class.

In that case you want Plants to be a friend of Color and not the other way around as you have it now.

#include "Color.cpp"

Don't include .cpp files. Only include header files.

[keskiverto]

You have friendship backwards. You give colours a full access to plants.

Other notes:
* Do not name headers with .cpp. While you could use any filenames, most tools (particularly IDEs) expect convention that .cpp is a source file.

* Do not use global variables, unless necessary. Global variable defined in a header is definitely a bad idea.

* class Foo {} bar; is same as

class Foo {};

Foo bar;

It is less confusing, when type definition is separate from the variable declaration(s).

[SomeAmazingGuy]

Ah I see, thank you for your response.

So when a friend class is declared inside another class, both classes have access to each others members right?

[MiiNiPaa]

No. friend declaration means "I give this class rights to touch my private parts". Not "I can touch your private parts whenever I want because I thinky you are my friend"