[kidb]

I think the trick is that array[i] and i[array] will always be the same value in C.

It's confusing because array[i] makes sense but i[array] doesn't (how the hell can you use an array as an index on an integer?)

It works because array is a pointer to a memory address and i (or index) is an offset. array[i] will add the index to the memory address and return the value there, where as i[array] will add the memory address to the index. Since array+index == index+array, they point to the same memory and return the same value.