What is the difference between these ways of indexing a pointer to an array of structs in c?

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4

Is there any difference in the use of these 3 statements?

void addCliente(struct cliente *dadosCliente){
    dadosCliente[k].nome="oi";
    (*(dadosCliente+k)).nome="oi";
    (dadosCliente+k)->nome="oi";
}
void main(){
    struct cliente clientes[1000];
    addCliente(clientes);
}
c pointer

  • How is the structure used? nome is a pointer, right?

  • 4

    No difference except for the readability. All will have the same effect.

  • 2

    The question is cool, but it’s not exactly about "statement" (or even "attribution") of strings, but about ways to access elements of a struct, isn’t it? In this case, I suggest editing at least the title to make it clearer.

1 answer

15


The three ways to access a struct in an array are equivalent.

Therefore:

  • (*(a+b)).c is (a+b)->c
  • (*(a+b)).c is a[b].c

  • and would have some more efficient than other?

  • 2

    No. They are exactly the same semantically. Just different ways of saying the same thing.

  • 3

    @user2984406: Compilers nowadays are very good at optimizing code, often greatly changing its structure. Accessing an array through the index in a well-defined loop allows the compiler to do these optimizations more easily, and makes the code much more readable for those who will do the maintenance later.

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