! error_demo1.f90

program error_demo1
  real, dimension(3) :: v
  real :: ans = 0.0
  
  print *, "error_demo1.f90 1.0e-7"
  v(1) = 1.0
  v(2) = 1.0e-7
  v(3) = -1.0
  do i=1,3
    ans = ans + v(i)
  end do
  ans = 1.0e10 * ans
  print *, "ans=", ans

  print *, "error_demo1.f90 0.5e-7"
  v(2) = 0.5e-7
  ans = 0.0
  do i=1,3
    ans = ans + v(i)
  end do
  ans = 1.0e10 * ans
  print *, "ans=", ans
  print *, "expression ans=", (1.0e10*((1.0+1.0e-7)-1.0))
end program error_demo1