Question

If we can use pointers and malloc to create and use arrays, why does the array type exist in C? Isn’t it unnecessary if we can use pointers instead?

Answer 1

Arrays are faster than dynamic memory allocation.

Arrays are “allocated” at “compile time” whereas malloc allocates at run time. Allocating takes time.

Also, C does not mandate that malloc() and friends are available in free-standing implementations.

---

Edit

Example of array

#define DECK_SIZE 52
int main(void) {
    int deck[DECK_SIZE];
    play(deck, DECK_SIZE);
    return 0;
}

Example of malloc()

int main(void) {
    size_t len = 52;
    int *deck = malloc(len * sizeof *deck);
    if (deck) {
        play(deck, len);
    }
    free(deck);
    return 0;
}

In the array version, the space for the deck array was reserved by the compiler when the program was created (but, of course, the memory is only reserved/occupied when the program is being run), in the malloc() version, space for the deck array has to be requested at every run of the program.

Arrays can never change size, malloc’d memory can grow when needed.

If you only need a fixed number of elements, use an array (within the limits of your implementation).
If you need memory that can grow or shrink during the running of the program, use malloc() and friends.