ClassCastException java.lang.Long cannot be cast to clojure.lang.IFn

Question

I have a function that takes the number of years and salary, then recursively doubles the salary until years is exhausted. However, I keep getting this error:

Answer 1

The error's meaning shouldn't be too hard to sort out: a number is being used where a function is expected.

Parenthesis in Clojure are not a grouping construct, they are used primarily to invoke function calls. If you change (salary) to salary you will return the number rather than attempting to call it as a no-argument function.