/* NetRexx */
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/*REXX program to sort an integer array.*/

numeric digits 20    /*handle larger numbers.*/
a = ''
a[ 1]=               1
a[ 2]=               0
a[ 3]=              -1
a[ 4]=               0
a[ 5]=               5
a[ 6]=               0
a[ 7]=             -61
a[ 8]=               0
a[ 9]=            1385
a[10]=               0
a[11]=          -50521
a[12]=               0
a[13]=         2702765
a[14]=               0
a[15]=      -199360981
a[16]=               0
a[17]=     19391512145
a[18]=               0
a[19]=  -2404879675441
a[20]=               0
a[21]= 370371188237525

size = 21                          /*we have a list of 21 Euler numbers.*/
tell('un-sorted', a, size)
a[0] = size
esort(a, 1)
tell('   sorted', a, size)

return

/*----------------------------------ESORT subroutine--------------------*/
method esort(a, size) public static
--esort: procedure expose a.;

  h = a[0]

  loop while h > 1
    h = h % 2
    loop i = 1 for a[0] - h
      j = i
      k = h + i
      loop while a[k] < a[j]
        t    = a[j]
        a[j] = a[k]
        a[k] = t
        if h >= j then leave
        j = j - h
        k = k - h
        end
      end i
    end

return

/*----------------------------------TELL subroutine---------------------*/
method tell(arg, a, size) public static
--tell:

  say arg.center(40, '-')
  loop j = 1 for size
    say arg 'array element' j.right(size.length)'='a[j].right(25)
    end j
  say

  return