program sort
   implicit none
   integer,parameter::numitems=10
   integer::i,comparisoncount = 0     ! ANALYSIS OF EFFICIENCY OF SELECTIONSORT
   integer,dimension(numitems)::item
   open(unit = 1,file = 'unsorted',status = 'old')
   open(unit = 2,file = 'sorted',status = 'new')
   do i = 1,numitems
    read(1,'(bz,i3)')item(i)
   end do
   call selectionsort(item)
   do i = 1,numitems
    write(2,'(i3)')item(i)
   end do
   print*,'There were',comparisoncount,'comparisons'
  contains
   subroutine selectionsort(x)
    implicit none
    integer,dimension(numitems),intent(inout)::x
    integer::i,j
    do i = 1,numitems-1
     do j = i+1,numitems
      if (x(i) > x(j)) call swapint(x(i),x(j))
      comparisoncount = comparisoncount + 1
     end do
    end do
   end subroutine
  end program

  subroutine swapint(x,y)
   implicit none
    integer,intent(inout)::x,y
    integer::temporary
    temporary = x
    x = y
    y = temporary
   end subroutine