Why does a recursed return call break out of stack without an explicit return statement?

Question

I was shown a sample program to demonstrate recursion which looks like it should not work but does. The logic is pretty clear but why does it work even when the recursed fu

Answer 1

Aren't you forgetting a return statement? For normal recursion you need to put a return before isprime(num,i-1); as well.

I guess this even should give a compile warning if you compile this using strict rules, because the function must always return an int, now it does not (at least if your compiler does not fix this).