Re: Benchmark games, Rust, big ints and Pi

[bearophile via Digitalmars-d-learn]

John Carter:

Your paste has expired / no longer there.... but the subject has come up again...

...
Do you still have your implementation hanging around?

I think it was this. *Untested*:


void main(string[] args) {
    import core.stdc.stdio, std.bigint, core.stdc.stdlib;

    immutable n = (args.length == 2) ? args[1].ptr.atoi : 100;
    BigInt acc, den = 1, num = 1;

    for (uint i, k; i < n; ) {
        immutable k2 = ++k * 2U + 1U;
        acc = (acc + num * 2U) * k2;
        den *= k2;
        num *= k;
        if (num > acc)
            continue;

        immutable d = ((num * 3 + acc) / den) % 10U;
        if (d != ((num * 4 + acc) / den) % 10U)
            continue;

        putchar('0' + d);
        if (++i % 10 == 0)
            printf("\t:%u\n", i);
        acc = (acc - den * d) * 10U;
        num *= 10U;
    }
}

Bye,
bearophile