Passing pointer or array to function

Question

It seems like if I have a fixed-size array in C I can pass it to a function as long as the argument of the function is either a pointer or an array with no specified size, e.g.:

int a[3] = {0, 1, 2};

void fn1(int *a);
void fn2(int a[]);

I also noticed that I can use standard member access and pointer arithmetic with both.

Is there any formal or functional difference between the two approaches? Logically I would think that the second one is better because it indicates that I am supposed to treat the input argument as an array, but that's just my guess.

Any hints will be appreciated.

int a[] in the function parameter list is just another way to write int *a. Thus there are no different approaches to compare and contrast. The two notations mean exactly the same thing, by definition. — n. m. could be an AI
– n. m. could be an AI, Commented Sep 12, 2020 at 17:16
a[] => *a conversion is done at compile time. Like s->a => (*s).a — Sathvik
– Sathvik, Commented Sep 12, 2020 at 17:16
In that case, is there any better formal approach or convention? — user3758232
– user3758232, Commented Sep 12, 2020 at 17:21
@user3758232 use int a[] because it is easily understandable/readable. But there is not difference between int a[] and int *p — Sathvik
– Sathvik, Commented Sep 12, 2020 at 17:23

Sathvik · Accepted Answer · 2020-09-12 17:37:55Z

2

Is there any formal or functional difference between the two approaches?

There is no formal or functional difference between those two approaches.

During compilation int a[] is converted to int *a. But for better readability use int a[] over int *a.

print (a[2]) is converted to print (*a + (2 * sizeof(int))).

edited Sep 12, 2020 at 17:37

answered Sep 12, 2020 at 17:31

Sathvik

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