/* NetRexx*************************************************************
* Forward differences
* 18.08.2012 Walter Pachl derived from Rexx
**********************************************************************/
  Loop n=-1 To 11
    differences('90 47 58 29 22 32 55 5 55 73',n)
    End

  method differences(a,n) public static
  --arr=Rexx[11]                       -- array must be declared (zero based)
    arr=''                             -- alternative: indexed string
    m=a.words
    Select
      When n<0 Then Say 'n is negative:' n '<' 0
      When n>m Then Say 'n is too large:' n '>' m
      Otherwise Do
        Loop i=1 To m
          arr[i]=a.word(i)
          End
        Loop i = 1 to n
          t = arr[i]
          Loop j = i+1 to m
            u = arr[j]
            arr[j] = arr[j]-t
            t = u
            end
          end
        ol=''
        Loop i=n+1 to m
          ol=ol arr[i]
          End
        Say n ol
        End
      End