Thread: Beginner looking at code that I need to know what it does

Hello,

I'm new to C and I have to look into someones code who has been doing it for many years. He is unavailable to help me so I hope someone on here can. I have worked with C# for many years, but some of the syntax doesn't seem to make sense.

For example :

Code:

struct dataBlk  
    {
    struct dataBlk *prevBlk;
    struct dataBlk *nextBlk;
    struct metaBlk *metaBlk;
    struct metaFld *metaFld;
    char *key;  
    char *data; 
    };

struct dataBlk
    *dataBlk = 0,
    *rootBlk = 0;

Is struct an object definition?

So is he creating objects within an object?

Why does he use struct dataBlk again after the initial struct definition?

Thank you for any help

Is struct an object definition?

Yes.

So is he creating objects within an object?

No. You missed out something. He's creating pointers to objects. You could also create objects within an object but that's not what is happening in the above code.

Why does he use struct dataBlk again after the initial struct definition?

After defining an object, you're free to create as many instances of the object as you would with. That is what the author is doing in like 11

Originally Posted by Aslaville

Yes.



No. You missed out something. He's creating pointers to objects. You could also create objects within an object but that's not what is happening in the above code.



After defining an object, you're free to create as many instances of the object as you would with. That is what the author is doing in like 11

Aslaville,

Thank you for your help.

I just looked and there is a struct for metaBlk and metaFld so those are pointers to those objects.

So when this code is executed

Code:

struct dataBlk
  *dataBlk = 0,
  *rootBlk = 0;

1. It is creating an object with pointers to prevBlk, nextBlk, metaBlk and metaFld?
2. What is the definition of *rootBlk? I checked the code and there is no definiton for it.
3. Why is *dataBlka and *rootBlk set to 0?

Sorry if these are obvious questions. I just want to try and understand the concepts from the basic level so I build on that.

Thank you again

Thank you Laserlight.

Can you explain this code some more:

Code:

struct dataBlk  
    {
    struct dataBlk *prevBlk;
    struct dataBlk *nextBlk;
    struct metaBlk *metaBlk;
    struct metaFld *metaFld;
    char *key;  
    char *data; 

    };

Once rootBlk is initialized are the structs within the definitions pointers to other objects?
How are these used?

*prevBlk;
*nextBlk;
*metaBlk;
*metaFld;
char *key;
char *data;

rootBlk.prevBlk = another dataBlk object?

Thank you

Thank you so much for making it clearer.
I'm looking up intro tutorials and going through them now. I do appreciate you help.