The Damm algorithm is a checksum algorithm which detects all single digit errors and adjacent transposition errors.



The algorithm is named after H. Michael Damm.



Task

Verify the checksum, stored as last digit of an input.



# Project : Damm algorithm
 
matrix = [[0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
               [7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
               [4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
               [1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
               [6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
               [3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
               [5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
               [8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
               [9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
               [2, 5, 8, 1, 4, 3, 6, 7, 9, 0]]
 
see "5724" + encode(5724 ) + nl
see "5727" + encode(5727 ) + nl
see "112946" + encode(112946) + nl
 
func encode(n)
       check = 0
       for d in string(n)
           check = matrix[check+1][d-'0'+1]
       next
       if check = 0
          return " is valid"
       else
          return " is invalid"
       ok