xv

def calc_check_digit(digits):
  digits = [int(i) for i in str(digits)][:-1]
  
  odd_pos_list = digits[0::2]  # 1st, 3rd, 5th, etc
  even_pos_list = digits[1::2] # 2nd, 4th, 6th, etc
  
  n = (sum(odd_pos_list) * 3) + sum(even_pos_list)
  rmndr = n % 10
  return (10 - rmndr) if rmndr > 0 else 0

xv

public static byte LOBYTE(ushort a) => 
    (byte)(a & 0xFF);

public static byte HIBYTE(ushort a) => 
    (byte)((a >> 8) & 0xFF);

public static ushort HIWORD(uint a) => 
    (ushort)((a >> 16) & 0xFFFF);

public static ushort LOWORD(uint a) => 

xv

#define MIN(A, B) ((A) < (B) ? (A) : (B))
#define MAX(A, B) ((A) > (B) ? (A) : (B))
#define CLAMP(N, LO, HI) (MIN(MAX((LO), (N)), (HI)))