将结构中的数据存储到另一个结构中

Question

Im doing something like a supermarket simulator using C. I have a struct that keeps data from hundreds of fictional clients like so:

typedef struct clients {
int ID;
char Name[50];
}Clients;

I imported a .txt file containing these clients. It basically looks like this:

1234 Peter Parker
4724 Barack Obama
3851 John Wick
9428 Donald Trump
...

So now I have to simulate a supermarket, i have a timer that updates itself, picking random clients from the struct and put them inside the supermarket, i need to keep track how many of them and which of them are inside the supermarket. The thing is, i don't know how to like put the clients inside the market and store the data of those clients. For example, imagine client A and B enter the supermarket, how do I store those specific clients in the market, so that like i could search which of them are inside the market? Should I make a struct containing data from the struct Clients? I have no idea. Glad if you could help me.

Answer 1

You can create an array of your clients struct.

Here are some resources I found. http://www.asic-world.com/scripting/structs_c.html http://www.c4learn.com/c-programming/c-array-structure/

Answer 2

First thing that comes to mind is to use some kind of directed (or bidirected) list containing references to your Client structure. For instance,

typedef struct {
  Client *client;
  Visitor *next;
  Visitor *prev;
} Visitor;

may be one of the nodes of that list. In the case of head or tail of the list, you can specify NULL values to distinguish different corner cases, but that depends on realization.

The list itself:

typedef struct {
    Visitor *head;
    Visitor *tail;
} VisitorList;

The drawback of such structure is that getting number of visitors has linear complexity which may be not that you want.

Answer 3

The answer is that there are many ways to do this, with pros and cons to each. If you care about performance and your data gets larger than hundreds and into the upper thousands then you probably start worrying about what type of data structure you're using, which then becomes a question about data structures and how you'll be searching for the names. If you're not so worried about performance, you can go for an array implementation where you create an array of Clients like so: which declares an array of 200 clients that you can assign values to.

Clients array[200];

The down side of this is if you get more Clients than you've allocated memory for, you'll have to either malloc more memory to fit it.

Alternatively you can go with the linked list implementation and create some sort of struct that represents a node with corresponding functions to manipulate it.

typedef struct {
  Client *client;
  node *next;
  node *prev;
} node;

But this would require writing more code to add and remove nodes at minimum.

So, its really question of what YOU want.

EDIT: If you just want to add a way of knowing if some client is in the super market why not create an enum and add it into the client struct ? I prefer this over bool because then if you want to put someone in another place in the future, then you have the option to just add it to the enum .

enum place {
    supermarket,
    none
};