C language memory alignment

1. The array is aligned by the alignment parameters of the element;
2. Set the alignment parameter: # pragma pack (n); cancel: # pragma pack ();
3. Select the alignment parameter of the type and the smaller alignment parameter n for each matching;
4. The final size of the struct is a multiple of the maximum member Alignment Parameters in the struct and the number of small ones in N. This serves as the basis for the number of bytes to be left blank after the last element;
5. The alignment parameter of the struct type itself is the alignment parameter of the maximum member type;