C code you should never use in production

Here’s a stupid little C trick which amuses me. Consider a C array:

char array[3] = {1,2,3};

To access element 3, you would use

array[2]

This is just shorthand for a pointer dereference

*(array + 2)

This is just addition, which is associative, so it’s the exact equivalent of

*(2 + array)

which gives you

2[array]

which is perfectly valid C.

To prove that, consider this simple program

void main()

{

char array[3] = {1,2,3};

printf("array[2]: %d. 2[array]: %d\n", array[2], 2[array]);
}

After compilation

./assoc.out
array[2]: 3. 2[array]: 3

I would strongly caution against ever using this in production. Your colleagues will worry about you if they see it during a code review or when working on code you wrote. If you don’t think they would flag it, you should be worrying about them instead.