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