Recursion is just induction backwards. But you need to know what a stack is - because it gives you the practical depth to which you can recurse. Ditto with tai

Recursion is just induction backwards. But you need to know what a stack is - because it gives you the practical depth to which you can recurse. Ditto with tail recursion optimization. And that is why C should be mandatory. You must be able to translate the mathematical concepts into something real and tangible.