Program perfect_square
!------------------------------------------------------------------------------
!Program: Perfect Square Test Function
!Author: Chris Harper
!Date: 2/24/2008
!------------------------------------------------------------------------------

IMPLICIT NONE

!declare functions and variables
logical :: isPerfectSquare
integer :: n

!test perfect square function with user input
do
	print *, "Enter an integer (-1 to exit):"
	read *, n
	if (n < 0) exit
	if (isPerfectSquare(n)) then
		print *, n, " is a perfect square"
	else
		print *, n, " is not a perfect square"
	end if
end do
end

!returns true if n is a perfect square, false otherwise
logical function isPerfectSquare(n)
	IMPLICIT NONE
	integer , intent (IN) :: n
	real :: root

	!if the square root has no decimal portion
	!test this with 'if sqrt == truncated decimal sqrt'
	root = sqrt(real(n))
	if (root == aint(root)) then
		isPerfectSquare = .true.
	else
		isPerfectSquare = .false.
	end if
end function