Question

I’ve searched around and haven’t found an answer to this. What I would like to know is this:

If I declare a static unsigned char const ARRAY[256] = { [0] = <some_value> };,
can I expect the unspecified elements (in this case all but the element at index 0) to have a certain value, or will they be random?

I need this for a constant lookup table that won’t have all elements filled, but isn’t too large, so wasting some space isn’t a problem.

Suggestions for more appropriate data types or conventions are welcome.

Thanks!

Answer 1

The rest of the array will be initialized to zero.

Also, you may initialize more than one element in the array, for example:

char arr[10] = {1, 2, 3};

will create and initialize the array arr to:

index | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
---------------------------------------------
value | 1 | 2 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0