!**********************************************
!*   Demonstration program of Bubble sorting  * 
!*        (about n*n comparisons used).       *
!* ------------------------------------------ *
!* Reference: "A book on C by Al Kelley and   *
!* Ira Pohl, The Benjamin/Cummings Publishing *
!* Company, Inc, 1984".                       *
!*                                            *
!*                F90 version by J-P Moreau.  *
!* ------------------------------------------ *
!* SAMPLE RUN:                                *
!*                                            *
!* Initial table A:                           *
!* 7  3  66  3  -5  22  -77  2  36  -12       *
!*                                            *
!* Sorted table A:                            *
!* -77  -12  -5  2  3  3  7  22  36  66       *
!*                                            *
!**********************************************
Program Bubble_sort

parameter(MAX=1024)

integer A(1:MAX)

  n=10
  A = 0
  A(1)=7;  A(2)=3;   A(3)=66; A(4)=3;  A(5)=-5
  A(6)=22; A(7)=-77; A(8)=2;  A(9)=36; A(10)=-12

  print *,' '
  print *,' Initial table A:'
  write(*,10) (A(i),i=1,n)
  print *,' '

  call Bubble(A,n)

  print *,' Sorted table A:'
  write(*,10) (A(i),i=1,n)
  print *,' '
  print *,' '
  stop
  
10 format(10I5)

END

!return p,q in ascending order
Subroutine Order(p,q)
integer p,q,temp
  if (p>q) then
    temp=p
    p=q
    q=temp
  end if
  return
end

!Buuble sorting of integer array A
Subroutine Bubble(A, n)
integer A(1:n)
  do i=1, n
    do j=n, i+1, -1
      call Order(A(j-1), A(j))
    end do
  end do
  return
end

!end of file bubble.f90