Hello everybody.

I'm starting a game dev career and I'm working on a project right now. It's a very basic text-based game; what I want to achieve here is the good use of code and it's methods.

The game is about a guy who wakes up in a room with objects to look. Once he finds a key, he goes to another room, where he should look up for a code to open box and get another key to exit.

What I did is separate each room into a function, called room1() and room2(); each of them has a do while loop where the games asks the user what object wants to see (say table, closet, desk, etc)

Now the problem that I'm having is handling the inventory. You start with no keys (3 in total) I created a class called Inventory where are 3 booleans. What I want to do is, when the user finds a key, "true" it so the user can use it in the next room (for example the same key to go back to room 1)

So far, in main() I have an instance of Inventory called inventory and make the objects false, then room1(); But (of course), when I go to room1() inventory doesn't exist. Is there a way I can reach and modifying in them globally? without passing them through the function name? (say room1(key1))

And is this the best/cleanest way of coding?

Thanks everybody !

Before I go off on a tangent about rooms being objects and using a manager class:

Do you understand how to use Object-Oriented Programming in C++?

And is this the best/cleanest way of coding?

well, its one way.

and about par for a first stab at it. IE we all started out that way. <g>.

for a small game, it would get the job done.

first thing i notice, you have a "game loop" (display contents, get and process input) for each room.

games typically have just one "game loop". in your case it might look something like:

while (! quitgame)

1. list contents of current room

2. based on current room, get and process user input

So far, in main() I have an instance of Inventory called inventory and make the objects false, then room1(); But (of course), when I go to room1() inventory doesn't exist. Is there a way I can reach and modifying in them globally? without passing them through the function name? (say room1(key1))

someone else here will have to help you with that, i stick mostly to c syntax myself. but don't worry, you'll get lots of suggestions. there tend to be many ways to skin a cat using c++ syntax.

but from an oo point of view...

off the top off my head, i'd say a room is a class, with data like a list of objects in the room, and methods like display_list and process_input.

then your game loop would look something like:

while (! quitgame)

room[current_room].display_list

room[current_room].process_input

where room[] is a list of room objects

and

current_room is a global of some sort, used by the game loop, but changed by the process_input methods when the player goes though a door. its is, in essence, a global "game state" variable, where each room is a "game state".

if keys are your only inventory item,you might use a "list of keys" object with 3 Booleans for keys 1,2, and 3, perhaps as an array BOOLEAN[3] or int[3], or BYTE[3]), and methods like add_key(key_num), remove_key(key_num) etc.

then your room[0].process_input method would call keylist.add_key(1) when they found the key to the next room. and perhaps keylist.addkey[0] when they find the key to the room they start in (so they can go back).

note that in applying oo design here, i'm thinking more in terms of data structures and the methods that use them (room contents data structure, inventory list data structure), and less in terms of "objects" (room, key).

from an objects standpoint, one would think "a room is an object", probably leading to a "list of room objects" data structure. but one would also think "a key is an object", probably leading to a list of keys objects, which is probably overkill. i mean, a class with one Boolean, and two methods, set, and clear? PLEEEZE! talk about OVER-ENGINEERING! <g>.

in the long run, you'll find the KISS principle (Keep It Stupid-Simple, IE so simple a total idiot could get it) to be a good friend when coding. it makes code easy to read, makes code easy to write, and often tends to be what runs the fastest.

Hello guys, thanks so much for your response.

Do you understand how to use Object-Oriented Programming in C++?

I have a background in OOP but I have many years I don't write any code, where do you think I should start?

games typically have just one "game loop". in your case it might look something like:

while (! quitgame)
1. list contents of current room
2. based on current room, get and process user input

That's a good one Norm, yes I believe that a game should have a "game loop", in my case, that holds the loop for each room.

And thanks Norm for that whole explanation.

What I'll do now is to post the code I have so far:

#include <iostream>
#include <stdio.h>

using namespace std;

class Inventory {
public:
    bool key1;
    bool key2;
    bool key3;
};

void room1();
void room2();

int main() {
    Inventory inventory;
    inventory.key1 = false;
    inventory.key2 = false;
    inventory.key3 = false;

    cout<<"N O   E X I T\n";
    room1();

    return 0;
}

void room1() {
    Inventory inventory;
    int num = 0;

    do {
        cout<<"\nWhat do you want to look?:\n";
        cout<<"1. Desk\n";
        cout<<"2. Table\n";
        cout<<"3. Door\n";
        cin>>num;

        if (num == 1) {
            cout<<"You found a key in the desk.\n";
            inventory.key1 = true;
        }

        else if (num == 2) {
            cout<<"A big table, nothing interesting.\n";
        }

        else if (num == 3) {
            if (inventory.key1) {
                cout<<"Now you can open and go to next room.\n";
                room2();
                break;
            }
            else {
                cout<<"Door is closed.\n";
            }
        }
    }
    while (num != 4);
}

void room2() {
    Inventory inventory;
    int num = 0;

    cout<<"Room 2.\n";

    do {
        cout<<"\nWhat do you want to look?:\n";
        cout<<"1. Sofa\n";
        cout<<"2. Closet\n";
        cout<<"3. Door back to room 1\n";
        cout<<"4. Main Gate\n";
        cin>>num;

        if (num == 1) {
            cout<<"A sofa, nothing interesting.\n";
        }

        else if (num == 2) {
            cout<<"An open closet, here you found another key.\n";
            inventory.key2 = true;
        }

        else if (num == 3) {
            room1();
            break;
        }

        else if (num == 4) {
            if (inventory.key3) {
                cout<<"T H E   E N D";
                break;
            }
            else {
                cout<<"Main gate, but is closed.\n";
            }
        }
    }
    while (num != 5);
}

What do you think?

Thanks so much for your help guys, I'm really happy to be here!

other than refactoring to make it a single loop, its mostly just cleanup and organization.

the key1 - key3 Booleans could probably be initialized in the constructor for the inventory class.

if you move main() to the bottom of the file, you don't need the forward declarations for room1 and room2. for procedural code like main() room1() and room2(), c code is meant to appear in the file from bottom up. ie the lowest level routine is the first thing in the file, and the highest level routine (main) is at the end. forward declarations are intended for use with circular references (A calls B, and B calls A), although its common to use them as you did, to "invert" the order of appearance of the functions in the source code, so the highest level (main) comes first, followed by lower level routines. apparently this is often done because it supposedly increases readability. the sad fact is that it actually tends to decrease readability due to the fact that the declaration and implementation have been split up into two sections of code in two different places. the result is additional searching, when trying to figure out someone else code written in this style. and even with your own code. if you need to check the implementation of a routine, odds are 50% of the time a search will find the forward declaration first, not the implementation. on top of all that, its more typing. and if you repeat the declaration in the implementation, then you have two copies of the declaration, both of which must be edited if the declaration changes. to me just it seems like a lot of unnecessary BS to go though just so you can read your file from top down, instead of bottom up, as C is intended to be laid out. right now in your project it may not seem like a biggie, but wait til you get a couple hundred unnecessary forward declarations going.

room1 can call room2 which can call room1 which can call room2, ad infinitum, all without returning. You seriously need to reconsider your design.

What happens if you don't type in a number. What happens if you enter the number that breaks out of the do...while loop.

Why don't you pass inventory to each function. You may as well just have a local bool hasKey in each function in the moment, because you can only find 1 key in each room and when you call another function you will forget you ever had any others, at the moment. Actually, you won't forget you had them since the contents of Inventory will be the contents of the stack, so it could be anything.

You can't find key3 anyway.

Sorry to be harsh...

To answer the OP's original question, if you want to access Inventory globally, without passing it to each function, then it needs to be declared globally, like this:

 
class TInventory
{
  public:
  Inventory() :
    key1(false), // initializer list
    key2(false), 
    key3(false) {}
 
  bool key1;
  bool key2;
  bool key3;
};
 
// Declares the Inventory variable globally, so it can be access from any function
TInventory Inventory;
 
int main()
{
  // Now Inventory is available in all functions, no need to declare it again

When you get better at classes, you'll do this better, but that's how you globally declare a variable.