尾递归浅谈

erlang:

bump(L) -> bump_acc(L, []).
bump_acc([], Acc) -> reverse(Acc);
bump_acc([H|T], Acc) -> bump_acc(T, [H+1|Acc]).
 
reverse(L) -> reverse_acc(L, []).
reverse_acc([], Acc) -> Acc;
reverse_acc([H|T], Acc) -> reverse_acc(T, [H|Acc]).

c#:

public static int FactorialRecursively(int n)
{
    return FactorialContinuation(n-1, r => n*r);
}
 
public static int FactorialContinuation(int n, Func<int, int> continuation)
{
    if(n == 0) return continuation(1);
    return FactorialContinuation(n-1, r => continuation(n*r));
}
 
//calc !10
FactorialContinuation(10, x => x);

推演：

FactorialRecursively(3)
-> FactorialContinuation(2, r => 3*r);
-> FactorialContinuation(1, r => 3*2*r);
-> FactorialContinuation(0, r => 3*2*1*r);
-> 3*2*1

javascript:

<html>
<script type="text/javascript">
    function factorialRecursively(n)
    {
        var func = function(r)
        {
            return n * r;
        }
        return factorialContinuation(n-1, func)
    }
 
    function factorialContinuation(n, func)
    {
        if(n == 0)  return func(1);
 
        var con = function(r)
        {
            return func(n*r);
        }
        return factorialContinuation(n-1, con)
    }
 
    var func = function(x)
    {
        return x;
    }
 
    var test0 = factorialRecursively(5);
    document.write("test0 val:" + test0);
 
    document.write("<br/>");
 
    var test = factorialContinuation(5, func)
    document.write("test val:" + test);
</script>
</html>