Thread: Give an ID

Well I'm making a program, and it is suposed to be a dyamic list of "Workers" that are composed by an:

- Name
- Contribute code
- ID

the word 'dynamic' tells you that youll need a pointer for your array ('list') of workers, that can change size (ie with malloc). the 'composed' term tells you that you need to create a struct called Worker, with 3 'fields'. see the FAQ on this site for how to define and use structs, and also how to use malloc if you dont know how.

to assign the ID, you can have a variable that starts off at the lowest value, say integer 1. when you create the first worker, assign that workers id to the 'global' id that keeps track. you then increment the id counter, then assign it again to the next worker that is created.

please give specific questions to any of the above if you have trouble (after reading the faq)

Originally Posted by nadroj

the word 'dynamic' tells you that youll need a pointer for your array ('list') of workers, that can change size (ie with malloc). the 'composed' term tells you that you need to create a struct called Worker, with 3 'fields'. see the FAQ on this site for how to define and use structs, and also how to use malloc if you dont know how.

to assign the ID, you can have a variable that starts off at the lowest value, say integer 1. when you create the first worker, assign that workers id to the 'global' id that keeps track. you then increment the id counter, then assign it again to the next worker that is created.

please give specific questions to any of the above if you have trouble (after reading the faq)

I know understand structs and malloc, I have wrote the code, but I still don't understand how to give an automatic ID, can you explain it better please?

Thanks in advance.

But I need it to put in a xml file (must read and interpretate it), so I don't get it. Because everytime I restart the program the ID is gonna be 0, so some workers are gonna be with the same ID. Another question, After I get the data from the worker, I need to put it in a xml file, and it is really confusing me.

Thanks in advance.

Well, one easy way to resolve this would be to save additional information in another file. Let's say we define two struct: one being the type you want the ID to be, and the other being a a "IDGenerator" type.

Code:

typedef unsigned int TypeID;

typedef struct
{
    TypeID nextID;
} IDGenerator;

You could think implementing functionality for...

• Returning a unique ID
• Reseting the ID generator to 0
• Loading ID information from a FILE
• Saving ID information to a FILE

Here's what the function prototype could looks like (note that there is different way to do so):

Code:

/* Return a unique ID */
IDGenerator giveUniqueID(IDGenerator i, TypeID *newID);

/* Reset IDGenerator */
IDGenerator resetIDGenerator();

/* Load IDGenerator information from a file */
IDGenerator loadIDGenerator(FILE *file);

/* Save IDGenerator information to a file */
void saveIDGenerator(IDGenerator i, FILE *file);

This is just an idea on how it could be done. This would be rather straighforward to implement. And won't be complicated to use. If you have additional question, ask.