On Thu, Jul 24, 2014 at 01:14:40PM +0000, Darren via Digitalmars-d-learn wrote:
> I have the following code in fac.d (modified from the factorial
> examples on RosettaCode):
>
> #!/usr/bin/rdmd
> import std.bigint;
>
> pure BigInt factorial(BigInt n) {
> static pure BigInt inner(BigInt n, BigInt acc) {
> return n == 0 ? acc : inner(n - 1, acc * n);
> }
> return inner(n, BigInt("1"));
> }
>
> void main(string[] args) {
> import std.stdio;
> BigInt input = args[1];
> writeln(factorial(input));
> return;
> }
>
> It (more or less consistently) on my machine will calculate 'fac
> 47610', and (more or less consistently) will core dump with a segfault
> on 'fac 47611'.
[...]
You're probably running out of stack space because of your recursive
function. Write it as a loop instead, and you should be able to go
farther:
pure BigInt factorial(BigInt n) {
auto result = BigInt(1);
while (n > 1)
result *= n;
return result;
}
T
--
Ignorance is bliss... until you suffer the consequences!
