Test if a number is fibonacci

Question

I know how to make the list of the Fibonacci numbers, but i don\'t know how can i test if a given number belongs to the fibonacci list - one way that comes in mind is genera

Answer 1

A Scala version-

def isFib(n: Int): Boolean = {

def checkFib(f1: Int = 1, f2: Int = 1): Boolean = {

if(n == f1 || n == f2) true
else if(n < f2) false
else checkFib(f2, f1+f2)

}

checkFib()

}