Is there any justification for addressing array like <number>[array]? [closed]

Question

Recently I saw an answer on a question where they explained that addressing arrays in this way <number>[array] is valid C code. How do square brackets work in C?

Example:

char x[] = {'A','B','C','D','E','F','G','H','I','J'};
printf("%d\n",5[X]);
//Will print 70 == 'F'

This kind of notation seems cumbersome and potentially confusing for everybody including the author.

Does this way of addressing arrays come with some justifiable advantage?

or

Can I continue with my life without worrying?

Answer 1

I have never encountered this in "real code" (i.e., outside of intentionally obfuscated things and puzzles with artificial limitations) so it would seem that it is quite universally agreed that this shouldn't be done.

However, I can come up with a contrived example where it might be considered by some (not necessarily me) a nicer syntax: if you have multiple pieces of data related to a single entity in a column, and you represent the rows as different arrays:

enum { ADA, BRIAN, CLAIRE };
const char *name[] = { "Ada", "Brian", "Claire" };
const unsigned age[] = { 30, 77, 41 };

printf("%s is %u years old\n", ADA[name], ADA[age]);

I will be the first to agree that this obfuscates the syntax by making it look like the people are the arrays instead of being the indexes, and I would prefer an array of struct in most cases. I think a case could be made for this being nicer-looking, though, or perhaps in some cases it would be a way to swap the rows and columns (arrays and indexes) with minimal edits elsewhere.