Task: SEDOLs

C: #include <stdio.h>
#include <ctype.h>
#include <string.h>

int sedol_weights[] = {1, 3, 1, 7, 3, 9}; 
const char *reject = "AEIOUaeiou";

int sedol_checksum(const char *sedol6)
{
  int len = strlen(sedol6);
  int sum = 0, i;

  if ( len == 7 ) {
    fprintf(stderr, "SEDOL code already checksummed? (%s)\n", sedol6);
    return sedol6[6] & 0x7f;
  }
  if ( (len > 7) || (len < 6) || ( strcspn(sedol6, reject) != 6 )) {
    fprintf(stderr, "not a SEDOL code? (%s)\n", sedol6);
    return -1;
  }
  for(i=0; i < 6; i++) {
    if ( isdigit(sedol6[i]) ) {
      sum += (sedol6[i]-'0')*sedol_weights[i];
    } else if ( isalpha(sedol6[i]) ) {
      sum += ((toupper(sedol6[i])-'A') + 10)*sedol_weights[i];
    } else {
      fprintf(stderr, "SEDOL with not alphanumeric digit\n");
      return -1;
    }
  }
  return (10 - (sum%10))%10 + '0'; 
}


#define MAXLINELEN 10
int main()
{
  char line[MAXLINELEN];
  int sr, len;
  while( fgets(line, MAXLINELEN, stdin) != NULL ) {
    len = strlen(line);
    if ( line[len-1] == '\n' ) line[len-1]='\0';
    sr = sedol_checksum(line);
    if ( sr > 0 )
      printf("%s%c\n", line, sr);
  }
  return 0;
}









COBOL:        >>SOURCE FREE
IDENTIFICATION DIVISION.
PROGRAM-ID. sedol.

ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    SELECT sedol-file ASSIGN "sedol.txt"
        ORGANIZATION LINE SEQUENTIAL
        FILE STATUS sedol-file-status.

DATA DIVISION.
FILE SECTION.
FD  sedol-file.
01  sedol                               PIC X(6).

WORKING-STORAGE SECTION.
01  sedol-file-status                   PIC XX.
    88  sedol-file-ok                   VALUE "00".

01  digit-num                           PIC 9 COMP.
    
01  digit-weights-area                  VALUE "1317391".
    03  digit-weights                   PIC 9 OCCURS 7 TIMES.
    
01  weighted-sum-parts-area.
    03  weighted-sum-parts              PIC 9(3) COMP OCCURS 6 TIMES.

01  weighted-sum                        PIC 9(3) COMP.

01  check-digit                         PIC 9.

PROCEDURE DIVISION.
    OPEN INPUT sedol-file
    PERFORM UNTIL NOT sedol-file-ok
        READ sedol-file
            AT END
                EXIT PERFORM
        END-READ

        MOVE FUNCTION UPPER-CASE(sedol) TO sedol
        
        PERFORM VARYING digit-num FROM 1 BY 1 UNTIL digit-num > 6
            EVALUATE TRUE
                WHEN sedol (digit-num:1) IS ALPHABETIC-UPPER
                    IF sedol (digit-num:1) = "A" OR "E" OR "I" OR "O" OR "U"
                        DISPLAY "Invalid SEDOL: " sedol
                        EXIT PERFORM CYCLE
                    END-IF
                
                    COMPUTE weighted-sum-parts (digit-num) =
                        (FUNCTION ORD(sedol (digit-num:1)) - FUNCTION ORD("A")
                        + 10) * digit-weights (digit-num)
                        
                WHEN sedol (digit-num:1) IS NUMERIC
                    MULTIPLY FUNCTION NUMVAL(sedol (digit-num:1))
                        BY digit-weights (digit-num)
                        GIVING weighted-sum-parts (digit-num)
                        
                WHEN OTHER
                    DISPLAY "Invalid SEDOL: " sedol
                    EXIT PERFORM CYCLE
            END-EVALUATE
        END-PERFORM

        INITIALIZE weighted-sum
        PERFORM VARYING digit-num FROM 1 BY 1 UNTIL digit-num > 6
            ADD weighted-sum-parts (digit-num) TO weighted-sum
        END-PERFORM
        
        COMPUTE check-digit =
            FUNCTION MOD(10 - FUNCTION MOD(weighted-sum, 10), 10)

        DISPLAY sedol check-digit
    END-PERFORM
    
    CLOSE sedol-file
    .
END PROGRAM sedol.