;;; -----------------------------------------------------------------------
;;  bmi.scm
;;  This program prompts the user for his weight in pounds and
;;  height in inches, computes the Body Mass Index (BMI) and displays
;;  "Underweight" if BMI is less than 18, "Normal" if BMI is between
;;  18 and 25, and "Overweight" if BMI is greater than 25.
;;  BMI is defined as weight, in kilograms, divided over the squared
;;  height, in meters.
;;; -----------------------------------------------------------------------

(define (BodyMassIndex weight height)
    ; Takes weight in kilograms and height in meters.
    ; Returns the value of BMI rounded to the nearest integer.
    (round->exact (/ weight (* height height)))  
)

(define (main)
    (let ((kgInPound    0.4536)   ; Declare some constants
	  (metersInInch 0.0254))
        (write-string "Enter your height in inches ==> ")
	(let ((height (* (read) metersInInch)))
	    (write-string "Enter your weight in pounds ==> ")
	    (let* ((weight (* (read) kgInPound))
		   (BMI (BodyMassIndex weight height)))
	        (write-string "Your BMI = ")
	        (write BMI)
	        (newline)  
	        (if (< BMI 18)
		    (write-line "Underweight")
		    (if (<= BMI 25)
		        (write-line "Normal")
		        (write-line "Overweight")
		    )
		)
	    )
	)
    )
    0  ; Return value
)