Question

I do not understand how I must go about this question the Scheme:

Use random to define a procedure fluctuate that takes a number x and returns one of the values x-2, x-1, x, x+1, or x+2, selected at random and with equal probability.

I tried using multiple randoms and adding x twice but I cannot find the answer can someone help?

Answer 1

Try this:

(define (fluctuate x)
  (+ x (- (random 5) 2)))

This is how it works:

• (random 5) generates random integers in the range [0, 4]
• Subtracting 2 from the previous range produces random integers in the range [-2, 2]
• Adding x to the previous result produces the values x-2, x-1, x+0, x+1, x+2 as requested

Notice that the random procedure selects a number at random and with equal probability by means of a pseudo-random number generator, the specific algorithm used depends on the implementation of your Scheme interpreter.