Programming Fundamentals/Conditions/Clojure

conditions.clj

;; This program asks the user to select Fahrenheit or Celsius conversion
;; and input a given temperature. Then the program converts the given 
;; temperature and displays the result.
;;
;; References:
;;     https://www.mathsisfun.com/temperature-conversion.html

(defn get-choice []
  (println "Enter C to convert to Celsius or F to convert to Fahrenheit:")
  (let [choice (read-line)]
    choice))

(defn get-temperature [choice]
  (println "Enter" choice "temperature:")
  (let [temperature (Float/parseFloat (read-line))]
    temperature))

(defn display-error []
   (println "You must enter C to convert to Celsius or F to convert to Fahrenheit."))

(defn calculate-celsius [temperature]
  (let [result (-> temperature
                   (- 32)
                   (* 5)
                   (/ 9))]
    result))

(defn calculate-fahrenheit [temperature]
  (let [result (-> temperature
                   (* 9)
                   (/ 5)
                   (+ 32))]
    result))

(defn display-result [temperature from-label result to-label]
  (println (str temperature "° " from-label "is " result "° " to-label ".")))

(defn main []
  (let [choice (get-choice)]  
    (cond 
     (or (= choice "C") (= choice "c"))
     (let [temperature (get-temperature "Fahrenheit")
                       result (calculate-celsius temperature)]
       (display-result temperature "Fahrenheit" result "Celsius"))
     (or (= choice "F") (= choice "f"))
     (let [temperature (get-temperature "Celsius")
                       result (calculate-fahrenheit temperature)]
       (display-result temperature "Celsius" result "Fahrenheit"))
     :else
     (display-error))))

(main)

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conditions.clj

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