结构或指针的结构？

Question

What is the best/fastest way ?

Struct of struct:

struct Sheet{
    u8 status; // to check if empty ?
    u8  reserve0;
    u8  reserve1;
    u8  reserve2;
    struct words words[1024];
};

struct Book {
    int id;
    struct Sheet sheet[64];
};

In this case, how to check if the sheet table is empty or not ? I need to add a status for each sheet ?

or

Pointer table of struct

struct Sheet{
    u8  reserve0;
    u8  reserve1;
    u8  reserve2;
    struct words words[1024];
};

struct Book {
    int id;
    struct Sheet* sheet[64];
};

I don't need to use malloc since they are fixed table.

In the struct of struct , I can initialize by setting status but for pointer to struct , I can initialize with bookinstance.sheet[] = NULL or something like this.

I am pretty lost with pointers , struct and malloc . I come from Ruby ...

To be clear:

I want not more than 64 sheet in my book instance. Maybe only 3 will be used or 64... But I want to be able to add them and check them with a number from 0 to 63.

Answer 1

To a certain extent it depend on what you mean by "faster". How your code will interact with these elements will change that. In general; however, there are very few times you would likely see any significant effect of CPU time.

Note that in option 2 Book only allocates an array of pointers so you will have to add code (and overhead) to allocate Sheets for the pointers to point to.

The first option would seem cleaner as long as you are not intending on some Sheets to be shared among books.

Also, if you are copying books, option 2 would be faster since you would only be copying pointer rather then the entire Sheet struct.