Task: IBAN



C#:     public class IbanValidator : IValidateTypes
    {
        public ValidationResult Validate(string value)
        {
            
            if (string.IsNullOrEmpty(value))
                return ValidationResult.ValueMissing;

            if (value.Length < 2)
                return ValidationResult.ValueTooSmall;

            var countryCode = value.Substring(0, 2).ToUpper();

            int lengthForCountryCode;

            var countryCodeKnown = Lengths.TryGetValue(countryCode, out lengthForCountryCode);
            if (!countryCodeKnown)
            {
                return ValidationResult.CountryCodeNotKnown;
            }

            
            if (value.Length < lengthForCountryCode)
                return ValidationResult.ValueTooSmall;

            if (value.Length > lengthForCountryCode)
                return ValidationResult.ValueTooBig;

            value = value.ToUpper();
            var newIban = value.Substring(4) + value.Substring(0, 4);

            newIban = Regex.Replace(newIban, @"\D", match => (match.Value[0] - 55).ToString());

            var remainder = BigInteger.Parse(newIban) % 97;

            if (remainder != 1)
                return ValidationResult.ValueFailsModule97Check;

            return ValidationResult.IsValid;
        }

        public enum ValidationResult
        {
            IsValid,
            ValueMissing,
            ValueTooSmall,
            ValueTooBig,
            ValueFailsModule97Check,
            CountryCodeNotKnown
        }

        private static readonly IDictionary<string, int> Lengths = new Dictionary<string, int>
        {
            {"AL", 28},
            {"AD", 24},
            {"AT", 20},
            {"AZ", 28},
            {"BE", 16},
            {"BH", 22},
            {"BA", 20},
            {"BR", 29},
            {"BG", 22},
            {"CR", 21},
            {"HR", 21},
            {"CY", 28},
            {"CZ", 24},
            {"DK", 18},
            {"DO", 28},
            {"EE", 20},
            {"FO", 18},
            {"FI", 18},
            {"FR", 27},
            {"GE", 22},
            {"DE", 22},
            {"GI", 23},
            {"GR", 27},
            {"GL", 18},
            {"GT", 28},
            {"HU", 28},
            {"IS", 26},
            {"IE", 22},
            {"IL", 23},
            {"IT", 27},
            {"KZ", 20},
            {"KW", 30},
            {"LV", 21},
            {"LB", 28},
            {"LI", 21},
            {"LT", 20},
            {"LU", 20},
            {"MK", 19},
            {"MT", 31},
            {"MR", 27},
            {"MU", 30},
            {"MC", 27},
            {"MD", 24},
            {"ME", 22},
            {"NL", 18},
            {"NO", 15},
            {"PK", 24},
            {"PS", 29},
            {"PL", 28},
            {"PT", 25},
            {"RO", 24},
            {"SM", 27},
            {"SA", 24},
            {"RS", 22},
            {"SK", 24},
            {"SI", 19},
            {"ES", 24},
            {"SE", 24},
            {"CH", 21},
            {"TN", 24},
            {"TR", 26},
            {"AE", 23},
            {"GB", 22},
            {"VG", 24}
        };
    }








Fortran: program ibancheck

   use ISO_FORTRAN_ENV

   implicit none

   character(4), dimension(75) :: cc = (/ &
            "AD24","AE23","AL28","AT20","AZ28","BA20","BE16","BG22","BH22","BR29", &
            "BY28","CH21","CR22","CY28","CZ24","DE22","DK18","DO28","EE20","ES24", &
            "FI18","FO18","FR27","GB22","GE22","GI23","GL18","GR27","GT28","HR21", &
            "HU28","IE22","IL23","IQ23","IS26","IT27","JO30","KW30","KZ20","LB28", &
            "LC32","LI21","LT20","LU20","LV21","MC27","MD24","ME22","MK19","MR27", &
            "MT31","MU30","NL18","NO15","PK24","PL28","PS29","PT25","QA29","RO24", &
            "RS22","SA24","SC31","SE24","SI19","SK24","SM27","ST25","SV28","TL23", &
            "TN24","TR26","UA29","VG24","XK20" /)

    character(34), dimension(12) :: ibans = (/ "GB82 WEST 1234 5698 7654 32       ", &
                                               "GB82WEST12345698765432            ", & 
                                               "gb82 west 1234 5698 7654 32       ", &
                                               "GB82 TEST 1234 5698 7654 32       ", &
                                               "GR16 0110 1250 0000 0001 2300 695 ", &
                                               "GB29 NWBK 6016 1331 9268 19       ", &
                                               "SA03 8000 0000 6080 1016 7519     ", &
                                               "CH93 0076 2011 6238 5295 7        ", &
                                               "IL62 0108 0000 0009 9999 999      ", &
                                               "IL62-0108-0000-0009-9999-999      ", &
                                               "US12 3456 7890 0987 6543 210      ", &
                                               "GR16 0110 1250 0000 0001 2300 695X" /)

    integer :: i
    
    do i=1, size(ibans)
        if (checkIBAN(trim(ibans(i)))) then
            print *, "  valid IBAN: ", trim(ibans(i))
        else
            print *, "invalid IBAN: ", trim(ibans(i))
        end if
    end do

    return
 
contains

    function checkIBAN(ibancode) result(valid)
        character(len=*), intent(in) :: ibancode
        character(len=len(ibancode)) :: iban
        logical :: valid
        integer(int32) :: j, ascii, ibanSize 
        character(100) :: ibanRearrange, ibantoint
        character(2) :: temp
        valid = .false.

        iban = remove_blanks(ibancode)
        ibanSize = checkCountryCode(iban)
        if (ibanSize == len(trim(iban))) then
            ibanRearrange = iban(5:ibanSize)//iban(1:4)
            ibantoint = ""
            do j=1, ibanSize
                ascii = ichar(ibanRearrange(j:j))
                if ((ascii >= 65) .and. (ascii<=90)) then
                    write (temp,fmt='(I2)') ascii-55
                    ibantoint = trim(ibantoint) // temp
                else
                    ibantoint = trim(ibantoint) // ibanRearrange(j:j)
                end if 
            end do
            if (mod97(ibantoint) == 1) then
                valid = .true.
            end if
        end if
    end function checkIBAN
    
    function mod97(strint) result(res)
        character(len=*), intent(in) :: strint
        integer :: i, num, res
        res = 0
        do  i=1, len(trim(strint))
            read(strint(i:i),*) num
            res = mod((res*10 + num),97);
        end do
    end function mod97

    function checkCountryCode(iban) result(ibanlength)
        character(len=*), intent(in) :: iban
        integer(int16) :: ibanlength, i
        ibanlength = 0
        do i=1, size(cc)
            if (iban(1:2) == cc(i)(1:2)) then
                read(cc(i)(3:4),*) ibanlength
                exit
            end if
        end do
    end function checkCountryCode
 
    Recursive Function Stripper(string,ch) Result(stripped)
        Implicit None
        character(len=*), intent(in) :: string
        character, intent(in) :: ch
        character(:), allocatable :: stripped

        IF (LEN(string)==1) THEN
           IF (string==ch) THEN 
              stripped = ''
           ELSE
              stripped = string
           END IF
        ELSE
           IF (string(1:1)==ch) THEN
              stripped = stripper(string(2:),ch)
           ELSE
              stripped = string(1:1)//stripper(string(2:),ch)
           END IF
        END IF
    END Function stripper

    Function Remove_Blanks(string) Result(stripped)
        Implicit None
        character(len=*), intent(in) ::   string
        character(:), allocatable :: stripped

        stripped = trim(Stripper(trim(Stripper(string,' ')),achar(9)))
    END Function Remove_Blanks

end program ibancheck