static RecursiveTask <int> Factorial(int n, int a)
{
if (n == 0)
{
return(a);
}
return(RecursiveTask <int> .FromFunc(() => Factorial(n - 1, n *a)));
}
static RecursiveTask <int> Fib(int n, int a, int b)
{
if (n == 0)
{
return(a);
}
if (n == 1)
{
return(b);
}
return(RecursiveTask <int> .FromFunc(() => Fib(n - 1, b, a + b)));
}