Tail Recursion
fac(n) = f1(1, n, 1);
fac(n) = n <= 1 ? 1 : n*fac(n-1);
f1(a, n, x) = x <= n ? f1(a*x, n, x+1)
: a;
tail-recursive
non-tail-recursive
There is
no Òmessy cleanupÓ after the inner function is called.
Good Housekeeping Seal of Approval
