program expression_equivalence ! simple evaluation of x*x-y*y ! when x and y are similar ! we will evaluate in three ways. implicit none real :: x = 1.002 real :: y = 1.001 real :: t1, t2, t3, t4, t5 t1 = x - y t2 = x + y print *, t1 print *, t2 t3 = t1*t2 t4 = x**2 - y**2 t5 = x*x - y*y print *, t3 print *, t4 print *, t5 end program expression_equivalence