int will be smaller than double on x86_64 (edit: x86 too, and most other platforms), but since in both structs int comes after the double, that doesn't matter.

int will be smaller than double on x86_64 (edit: x86 too, and most other platforms), but since in both structs int comes after the double, that doesn't matter. 400 is a multiple of 8, so it doesn't matter if it's before or after the double either.