Help with using private members outside of a class?

[AceDawg45]

I think this goes here. Yeah, it does.

Anyway, I always have trouble with this. Say, I make a class called "super.h" and it looks like this (note: this is just an example, I am not working on something like this):

"super.h"

class super{
    public:
        super(sObject);
    private:
        int a, b;
        super sObject;
};

And then I make a second class "cl.h" and it looks like this:

"cl.h"

class cl{
    public:
        cl();
    private:
        int c, d;
};

and then I make... a calculator function in the "super.cpp" (assume I prototyped it in "super.h".

void super::calculator()
{
    cout<<"A: ";
    cin>>a;
    
    cout<<endl<<"B: ";
    cin>>b;
    
    cout<<endl<<endl<<a+b;
}

Then I make the same thing in "cl.cpp":

"cl.cpp"

#include "super.h"
#include "cl.h"
#include <iostream>
using namespace std;

cl::cl(sObject)
: sObject.a(c), sObject.b(d)
{
    
}

void cl::cl_calculator()
{
    sObject.calculator();
}

I don't think that even works, but i am in a rush and made a quick little program in Code::Blocks, so I didnt really pay close attention. Anyway, it wouldnt let me use sObject.a and set it to c, the debugger would always say, "a member is private." I know it is but how do I make it to where it can work? Remember I am in a rush and didnt pay attention to this so I may edit it when I have time in the morning.

[qmzh85]

Since you set c and d as private, so there's no way to assign values to c or d.
You can set c and d as public, then you can do anything with them.
Or you can refer to the tutorial in this site:
http://www.cplusplus.com/doc/tutorial/classes/
where some simple examples illustrate the basics of class.

[LB]

Private data members exist for a reason - look up data hiding and data abstraction.

[AceDawg45]

OOOoohh yeah I remember that in a tutorial I watched. Thanks qmzh85. But... just one thing... I thought you weren't supposed to make variables public, because of hackers and stuff?

[qmzh85]

You are right, AceDawg45. We cannot simply put anything into "public". As L B mentioned, private data members exist for a reason.

I am also new to C++, that's only my limited understanding. Definitedly there would be many other better ways to handle this problem.

[LB]

AceDawg45 wrote:

because of hackers and stuff?

A hacker would disregard any language you used and just change the raw memory. It is up to the operating system, not you or your program, to defend against that.

[AceDawg45]

Really L B? Wow I didnt know it was up to the OS. I dont really know much about hacking, I always thought it was like, getting into the network and messing up the code of stuff. I program good things, I dont intend to learn hacking (not yet at least)

[LB]

My point is, making data members private provides no protection of any kind when the program is in binary form or is running in memory - it is only useful during compilation of the program.