program bsort
c
c -- test sort routine
c -- function rand and subroutine sort needed
c -- figure 6.2
c     
      integer length, out, max, i, beep
      real x(500)
      common /inout/ out, max
      data beep/7/
c
      out = 6
      max = 500
10    call input(x, length)
      write(out, 105) (x(i), i = 1, length)
      write(out, 101) beep
c -- random list
      call sort(x, length)
      write(out, 101) beep
      write(out, 105) (x(i), i = 1, length)
      write(out, 102) beep
c -- sorted list
      call sort(x, length)
      write(out, 101) beep
      write(out, 105) (x(i), i = 1, length)
      write(out, 103) beep
      do 20 i = 1, length
       x(i) = length + 1 - i
20    continue
      write(out, 101) beep
c -- reversed list
      call sort(x, length)
      write(out, 101) beep
      write(out, 105) (x(i), i = 1, length)
      write(out, 104) beep
      goto 10
101   format(' ', a1)
102   format(' random', a1)
103   format(' sorted', a1)
104   format(' reversed',a1)
105   format(1x, 10f7.2)
      end
      subroutine input(x, n)
c
c -- get n and generate random vector x
c
      integer n, out, i, max
      real x(1)
      common /inout/ out, max
c
5     write(out, 101)
      read(*,102) n
      if (n .gt. max) goto 5
      if (n .lt. 0) goto 99
      do 10 i = 1, n
       x(i) = rand(0) * 100.0
10    continue
      return
99    stop
101   format(' how many points? ' )
102   format(i3)
      end