05 October 2015   7:47:04.492 AM
 
LUHN_PRB
  FORTRAN90 version
  Test the LUHN library.
 
CH_IS_DIGIT_TEST
  CH_IS_DIGIT is TRUE if a character represents a digit.

   C      CH_IS_DIGIT(C)

  "0"  T
  "1"  T
  "2"  T
  "3"  T
  "4"  T
  "5"  T
  "6"  T
  "7"  T
  "8"  T
  "9"  T
  "X"  F
  "?"  F
  " "  F
 
CH_TO_DIGIT_TEST
  CH_TO_DIGIT: character -> decimal digit

   C      CH_TO_DIGIT(C)

  "0"         0
  "1"         1
  "2"         2
  "3"         3
  "4"         4
  "5"         5
  "6"         6
  "7"         7
  "8"         8
  "9"         9
  "X"        -1
  "?"        -1
  " "        -1
 
S_DIGITS_COUNT_TEST
  S_DIGITS_COUNT counts the digits in a string.

  We count  7 digits in "34E94-70.6"
  We count  0 digits in "Not a one!"
  We count  3 digits in "!8*k >>>> & SEVEN-0.3"
 
S_TO_DIGITS_TEST
  S_TO_DIGITS: string -> digit vector

  Test string: "34E94-70.6"
 
  Extracted 5 digits:
 
         1:             3
         2:             4
         3:             9
         4:             4
         5:             7

  Test string: "34E94-70.6"
 
  Extracted 7 digits:
 
         1:             3
         2:             4
         3:             9
         4:             4
         5:             7
         6:             0
         7:             6
 
LUHN_CHECK_DIGIT_CALCULATE_TEST
  LUHN_CHECK_DIGIT_CALCULATE calculates the check digit
  for a string of digits

  Check digit of "7992739871" is 3, expecting 3
  Check digit of "9876234510" is 0, expecting 0
  Check digit of "246897531" is 9, expecting 9
  Check digit of "135798642" is 9, expecting 9
 
LUHN_IS_VALID_TEST
  LUHN_IS_VALID determines whether a string with final
  Luhn check digit is valid.

  Validity of "79927398713" is T, expecting T
  Validity of "79924398713" is F, expecting F
  Validity of "79927398711" is F, expecting F
 
LUHN_PRB
  Normal end of execution.
 
05 October 2015   7:47:04.492 AM