Ex 13.1 uses parallel processes to compute factorials. Although this is not an efficient way to do it, it does illustrate the use of Concurreny::combine

I generated a similar solution to the downloaded version, but I concluded that it was only suitable up to 20! using a unsigned long long (or _int64) but the downloaded solution tries to calculate (25!, 49! and 50!) and I think the result are wrong above 20!.

Has anyone developed another solution, do I need a bignum library to solve it above 20! ?