anchor.diff:  
   ! Output start message
   
  -  write(*,'(A)'),"Calculating PI using:"
  -  write(*,'(A,1I16,A)'),"                  ",num_steps, " slices"
  -  write(*,'(A,1I16,A)'),"                  ",1," process"
  +  write(*,'(A)') "Calculating PI using:"
  +  write(*,'(A,1I16,A)') "                  ",num_steps, " slices"
  +  write(*,'(A,1I16,A)') "                  ",1," process"
   
   ! Initialise time counter and sum: set step size
   
  
positive.code:   implicit none
  
    double precision  :: step, x, sum, mypi, start, stop
    integer(kind=8)   :: num_steps, i
    character(len=32) :: arg
  
    num_steps = 1000000000
  
negative.code: ! output value of PI and time taken
  ! note cpu_time is only specified as being microsecond res
  
    write(*,'(A,1F12.10,A)') "Obtained value of PI: ", mypi
    write(*,'(A,1F12.5,A)') "Time taken:           ",(stop-start), " seconds"
  
  end program pi
  
  