Modulus 11 calculation not returning correct remainder - HELP

Question

Hi,
Algorithm check for 10 char alpha, first 9 chars are numeric and last is alpha which is derived at by: remainder of:-
(digit1*512 + digit2*256 + digit3*128 + digit4*64 +
digit5*32 + digit6*16 + digit7*8 + digit8*4 +digit9*2)/11
where digit 1 is the high order digit
The table is:
S for remainder 0
A 1
C 2
X 3
B 4
J 5
K 6
H 7
T 8
L 9
V 10
for example:
'555123321B' should return 4, otherwise fail
'999999999C' should return 2, otherwise fail
I'm in the process of constructing a method for a particular mod 11 calculation, and as a TEST, i have written the following code which is not working as i get the wrong remainder:
String sti = null;
sti= request.getParameter("sti");
int sum = 0; int rem = 0;
int sti_char1 = Integer.parseInt(sti.substring(0,1));
int sti_char2 = Integer.parseInt(sti.substring(1,2));
int sti_char3 = Integer.parseInt(sti.substring(2,3));
int sti_char4 = Integer.parseInt(sti.substring(3,4));
int sti_char5 = Integer.parseInt(sti.substring(4,5));
int sti_char6 = Integer.parseInt(sti.substring(5,6));
int sti_char7 = Integer.parseInt(sti.substring(6,7));
int sti_char8 = Integer.parseInt(sti.substring(7,8));
int sti_char9 = Integer.parseInt(sti.substring(8,9));
sum = (sti_char1 * 512 + sti_char2 * 256 + sti_char3 * 128 +
sti_char4 * 64 + sti_char5 * 32 + sti_char6 * 16 +
sti_char7 * 8 + sti_char8 * 4 + sti_char9 * 2)/11;
rem = sum % 11;
Can someone please help me write a for loop using a table array for this algorithm check?

Answer 1

ahh.. silly me. thanks.
anyone want to have a go at converting this C function to JAVA?
sti_validation(char *sti, char *msg) {
   char chr_arr[TWO_SZ];
   int  str_len;
   char *p;
   char *q;
   char *error_message;
   short i=0;
   int chr;
   int chkd=0,digit;
   int num[] = { 512, 256, 128, 64, 32, 16, 8,4,2 };
   static char* check_digit_tbl[] = {"S","A","C","X","B","J","K","H","T","L","V"};
   error_message = msg;
   str_len = strlen(sti);
   if ((str_len > 10) || (str_len < 10)) {
      sprintf(error_message,"String length must be 10 characters\n");
      return(0);
   for (p = sti; *p != '\0'; p++) {
      *p = toupper(*p);
      i++;
      if ((i >= 1) && (i <= 9)) {
         if( *p >= '0' && *p <= '9') {
            chr = *p;
            digit = (chr-'0');
      chkd = chkd + digit * num[i-1];
         }else {
            sprintf(error_message,"Characters 1 to 9 must be from 0 to 9\n");
            return(0);
      }else if (i = 10) {
         chkd = chkd % 11;
         sprintf(chr_arr, "%s",check_digit_tbl[chkd]);
         q = chr_arr;
         if( *p >= 'A' && *p <= 'Z') {
            if (*p == *q) {
            }else {
               sprintf(error_message,"Invalid last character\n");
               return(0);
         }else {
            sprintf(error_message,"Character 10 must be from A to Z\n");
            return(0);
      }/*i fr 1 to 9*/
   }/*For*/
   return (1);
}