Constants in Racket

Our program demonstrates the use of constants, using a simple example to illustrate their behavior in the racket language.

#lang racket

(define s "constant")

(define (main)
  (displayln s)

  (define n 500000000)
  (define d (/ 3e20 n))
  (displayln d)
  (displayln (inexact->exact d))

  (require math)
  (displayln (sin n)))

(main)

In this program, we declare a string constant s with the value "constant" and display it. We also declare a numeric constant n with the value 500000000, and perform some arithmetic with another constant 3e20 divided by n, storing the result in d. We then display d and its exact representation using inexact->exact. Finally, we demonstrate how the sin function from the math library can be used with the numeric constant n.

To run the program, create a file named constants.rkt and use the Racket interpreter:

$ racket constants.rkt
constant
6.0e11
600000000000
-0.28470407323754404

This will execute the Racket program and display the output of our constants and the calculated values.