program main

!*****************************************************************************80
!
!! MAIN is the main program for SUM_MILLION.
!
!  Discussion:
!
!    SUM_MILLION is a sketch of a program to generate the numbers
!    from 1 to 1,000,000, add them, and print the result.
!
!    This program is only a sketch.  Your job is to finish it,
!    debug it, and get it to run.
!
!    Read the CPU clock this way:
!
!      call cpu_time ( ctime1 )
!
  integer, parameter :: n = 1000000

  double precision ctime
  double precision ctime1
  double precision ctime2
  double precision error;
  double precision, parameter :: exact = 500000500000.0D+00
  integer flops
  integer i
  double precision mflops
  double precision total
  double precision x(n)

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'SUM_MILLION:'
  write ( *, '(a)' ) '  FORTRAN90 version'
  write ( *, '(a)' ) ' '
  write ( *, '(a,i8)' ) '  Task: add the numbers from 1 to ', n
!
!  Step 1:
!  Load the array X with the values.
!
  do i = 1, n
    x(i) = i
  end do
!
!  Step 2:
!  Start the clock.
!  Add up the entries in X.
!  Stop the clock.
!  Compute elapsed CPU time;
!  Set the number of FLOPs. (how many additions are being done?)
!  Compute the MFLOPS rate.
!  Compute the error.
!
  MISSING CODE
!
!  Step 3:
!  Print results.
!
  write ( *, * ) ' '
  write ( *, * ) '  Total     = ', total
  write ( *, * ) '  Error     = ', error
  write ( *, * ) '  CPU time  = ', ctime
  write ( *, * ) '  MegaFlops = ', mflops

  stop
end