e-Day

[Thomas Klemm]

(07-03-2018 11:25 PM)Valentin Albillo Wrote:  The C program posted by Mr. Klemm was obviously taken from the book "Obfuscated C and other mysteries", page 260.

Nah, I found it in Pi Unleashed by Arndt, Jörg, Haenel, Christoph on page 36.

Quote:It's a very interesting book, I can heartily recommend it.

Pi Unleashed is another book that we full-heartedly recommend.

Later on page 85 they show this small program that calculates e to 15,000 places:

Code:

/* note: N=15000, LEN=87700 >= 1.4*N*log10(N), 84700=LEN-N/5 */
a[87700],b,c=87700,d,e=1e4,f=1e5,h;
main(){for(;b=c--,b>84700;h=printf("%05d",e+d/f),e=d%=f)
for(;--b;d+=f*(h?a[b]:e),a[b]=d%b,d/=b);}

Both programs use the spigot algorithm to calculate e.

Cheers
Thomas

PS: Here's a link to Roemer B. Lievaart wining contribution of 1989 for the best layout.