Is that piece of code redundant?

Question

I recently did a C proof in which I had to complete a code to remove items from a queue, follow the code with the answer considered correct highlighted:

typedef struct No {
  int dado;
  struct No *proximo;
};

typedef struct Fila {
  struct No *inicio;
  struct No *fim;
}; 

struct Fila *filaDePosts;

int filaRemover(){
 struct No* ptr_no = fila->inicio;
 int dado;

 if (ptr_no != NULL) {
    **fila->inicio = ptr_no->proximo;**
    **ptr_no->proximo = NULL;**
    dado = ptr_no->dado;
    free(ptr_no);
    return dado;
 }
}

In the code snippet ptr_no->proximo = NULL;, whereas just below I execute the command free(ptr_no); which will already release the memory allocated to the struct ptr_no and its internal variables, it is redundant and unnecessary to cancel the value?

Answer 1

Yes, it seems redundant, it is changing a data that is not used later in an object that will soon be destroyed.

Taking advantage could have declared dado direct in its use and would have a less redundant code. And could have used a type in the typedef to avoid the redundancy of using struct.

typedef struct no {
    int dado;
    struct no *proximo;
} No;

typedef struct {
    No *inicio;
    No *fim;
} Fila;

I put in the Github for future reference.

In the code also no longer need to use struct.