~ prime.mse - lrb - 2/15/2007, 3/24/2007, 9/16/25

"!Enter a number in the range [2,32757] : " ?Q:
"!Do you want to check "
"1. this number only or 2. the range " Q. ! " " Q. 10+ !
"!1 or 2 ? "
? o: ~ use an integer variable, not a character variable - not sure why
o.1= ["!"Q.!" : "#G,Q.,2;]
o.2= [Q.1-l:Q.10+Q:(Q.l.-^"!"Q.!" : "#G,Q.,2;Q.1-Q:)]
"!"

~ find a prime factor of 1% using 2% as the initial candidate

$G 1%n:2%f:
~ 2 is special; if it's a candidate and not a divisor, start w/ 3
2%2=[n.2\[3f:]]
(n.f.\^f.2+f:) ~ f is now the smallest factor of n
~ next line figures out how often f goes into n
1c: n.f./d: f.g: (d.f.\0= ^ 1c.+c: d.f./d: g.f.*g:)
~ print it (possibly with an exponent) followed by a space
f.!c.1>['^!'c.!]" "
g.n.<[#G,d.,f.;] ~ call self if not done
f.Q.=["is prime."]@