Passing an array as function argument without defining a variable

Question

How can we pass an array directly to a function in C?

For example:

#include <stdio.h>

void function(int arr[]) {};

int main(void) {
    int nums[] = {3, -11, 0, 122};
    function(nums);
    return 0;
}

Instead of this, can we just write something like function({3, -11, 0, 122});?

One option is to wrap the array inside a struct: `struct foo { int arr[10]; }; struct foo wrapped = {{3, -11, 0, 122}}; fx(wrapped);` — pmg, Jan 11 '21 at 08:06
Ah! Didn't read the question title with enough attention; anyway leaving the comment here :-) — pmg, Jan 11 '21 at 08:08
@pmg Not your fault sir, I expanded the title based on my understanding of the question. the initial version had no mention of that. Apologies. — Sourav Ghosh, Jan 11 '21 at 08:10
*"can we just write something like"* - What happened when you tried? — klutt, Jan 11 '21 at 08:11

score 6 · Accepted Answer · answered Jan 11 '21 at 08:03

6

You can make use of a compound literal. Something like

function((int []){3, -11, 0, 122});

answered Jan 11 '21 at 08:03

Sourav Ghosh

One of those things that work in C but not C++, I think. – dxiv Jan 11 '21 at 08:09
@dxiv: it works in C99 and later, but not in C++ (yet?). – chqrlie Jan 11 '21 at 08:10

score 4 · Answer 2 · answered Jan 11 '21 at 08:03

4

You could pass array as compound literal as below.

function((int []){3, -11, 0, 122});

answered Jan 11 '21 at 08:03

kiran Biradar

2 Answers2