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[Boksi]

Because it's up in the clouds and you're going to scream a lot?

[Outcast Orange]

The HFS will be in the sky, and will have a large impact on the game.
I thought the name fit pretty well.

Apparently, Alfie has figured something out, which means this thing is moving along again.
I'm in the process of converting the whole thing into a class-based version of itself,
so a lot is being done, but with very few outward differences.

[Outcast Orange]

Okay, since I have no grasp of how London time works,
I'm going to ask my fellow creatives for help.

How do I access a public variable from another class?

The only way I know how is classinstance.variablename;,
but that only works when an instance has already been declared.

Any help will be appreciated.

Also, how long from now will it become 6 in London?

[Alexhans]

Theoretically, there's no reason as to why you would do that.  You need to make your variables private (or protected in case you use inheritance) and make public methods that will manipulate those variables.  So, eventually, you need to know nothing about the definition of the function, just the declaration.
If you use correct OPP you can change the structure of your class and the code will still work.  If you use public variables you'll need to change it everywhere.

I suggest you read this:
http://www.learncpp.com/cpp-tutorial/82-classes-and-class-members/
http://www.learncpp.com/cpp-tutorial/83-public-vs-private-access-specifiers/
and the following OOP articles wouldn't hurt either...

[timmeh]

The current time in London

Hmm... I may have to read the OOP articles too... I know how private and public work, but I'm sure I could be more efficient with my classes and such...

[Outcast Orange]

Thanks guys, you are very helpful.

EDIT:

So if I have an instance of lets say THIEF, it would never need to know the contents of HOUSE?
Shouldn't HOUSE's variables be public, so people moving around inside of it can interact with it?
How do I allow a member of class THIEF to get information about class HOUSE?

Also, this is all hypothetical. I am not making a burglary game presently.
(Though I have made one in the past) : )

[Ironhand]

If your variables are private, you can write public accessor methods for those variables.
Then rather than directly modifying house.loot, you call house.setLoot(), or whatever.

[Alexhans]

So if I have an instance of lets say THIEF, it would never need to know the contents of HOUSE?
Shouldn't HOUSE's variables be public, so people moving around inside of it can interact with it?
How do I allow a member of class THIEF to get information about class HOUSE?

You wouldn't need to know the body of the functions (The definition) but you'd know the name, return type and parameters of the functions so you can use them.  Like you do with every other class:
iostream, string, math, etc... those are all classes... you don't access their variables directly but the methods that access those variables.

Code: [Select]

//in the header
class House
{
private:
int nRooms;
bool bTaken;
std::string szAddress;
public:
//Get
//this are declarations
int GetRooms(); 
//...
//Set
void SetRoom(int ro);
//Other functions
void AddRooms(int amount);
//Constructors
House();  //default
House(int ro, bool tak, std::string ad);
//Destructor
~House();
};
//end of header...
This is all you need to know... the declarations and a good documentation telling what does each of them do.

Then comes the .cpp.

Code: [Select]

#include "nameofheader.h"

//defintions per se
int House::GetRooms() {return nRooms;}
//etc.

[Outcast Orange]

I think what I was trying to do was pointless.
The code I was trying to stuff into a class didn't really belong there.
Basically, my game flow has a large function called inputloop.
This is an endlessly looping list of possible actions based on input and circumstance.
I was trying to stuff it into a class, but it probably just belongs as its own function in its own cpp.

Sorry about that.

[Outcast Orange]

The more I play around with this, the more I think inputloop should be a class.
It has all of these extra (should be private) variables to keep track of itself.
bool inputgo; is a good example.
This tests if an action is allowed to be taken or not.
Any input?

[qwertyuiopas]

All that stuff about public vars vs. private with accessors

Do you know WHY you should? If you know WHY, you can infer WHEN, because nothing is universally best.

Yes, if you think that you may one day want to change it so that

int House::GetRooms() {return nRooms;}

is

int House::GetRooms() {return nRooms-nSecretRooms+nKnownSecretRooms();}

it would be better. However, sometimes it's better to directly use the variable.


It seems that most standards(such as avoid GOTO) are in place to ensure that the code can be altered or expanded without breaking anything.

So if I have an instance of lets say THIEF, it would never need to know the contents of HOUSE?
Shouldn't HOUSE's variables be public, so people moving around inside of it can interact with it?
How do I allow a member of class THIEF to get information about class HOUSE?

Making the contents public is fine as long as you don't mind limiting future expansion. Making it private with accessors is fine as long as you don't mind a potential slight speed loss(if the compiler doesn't just realize that both ways do the same thing, and optimize it for you), and scattering the logic of the code a bit more(though with decent naming, this shouldn't be a problem).


Go with what you feel is best, because some/many/all standards are there to make things easier in the long run, not simpler in the short run, and since you are learning a new subject, you want easier above all, at least until you understand why the standards exist.

-new post-

State variables? Are they just used in a single function?

If so, you may optionally make them static variables within the function, though it probably isn't good OOP, since if you ever were to break it up, you would have to promote them the class vars or global-to-the-file vars.

[Outcast Orange]

I found a way for input to work fine without variables, but I have a new problem.
Here are the basics:

These are two lines in my main, before the loop:

Code: [Select]

int samus;
#include "inputloop.cpp"

These are the first two lines of my input loop:

Code: [Select]

void inputloop(){
    samus = 1;

Why am I getting the "samus was not declared in this scope" error?

[Alexhans]

First, The main needs to include the "header.h" file... not the .cpp

-class.h will declare the class
-class.cpp will define the functions of the class (and include the class), you'll need to use the scope operators.
-main will include the class.h

To use the scope operator...

IT's "::".

Code: [Select]

ClassName::ClassFunction(<parameters>)
{
  /*Now you can use the implicit this-> pointer to access the elements of your class*/
return this->nRooms;
return nRooms;  /*this is the same but with the implicit pointer to the current object*/

}
I've just come back from running some errands (Buying stuff for a friend's party And I have other things to do outside but I'll have more time tomorrow to answer any doubts (or maybe today between (19-20hs GMT -3)...

See ya.

EDIT:  Btw, static variables can be useful within a class for certain things... For example, keeping track of the number of instances you create... Those static variables will need to be modified through static functions.  A static function and variable have the characteristic of belonging to all the instances of a particular class at the same time.

qwerty:  Don't worry so much about performance at this point.  Performance won't suffer for just using classes.  At this level it depends much more on how he structures the program and the efficiency of his algorithms.

[qwertyuiopas]

#include files literally puts the code of one file into another.

[Outcast Orange]

Okay. This has gotten much further along today.
I now have a tile class, and some basic functions.
I'll be figuring out how to get my universe creation in tomorrow hopefully.
I can't wait for this whole thing to be in classes,
the changes me and Alfie worked out will save tons of time on the programming side later.
It's a great investment, considering the game probably won't be able to move on without it.