% Prolog version of a Prime Number Finder
% haplo@mindstab.net

check(I,C,M,P) :-
	P \= 0,
	I > M.

check(I,C,M,P) :-
	P \= 0,
	NP is C mod I,
	NI is I + 2,
	check(NI,C,M,NP).

primes(M) :-
	nl, primes(3,M,2).

primes(C,M,S) :- C > M.
primes(C,M,S) :-
	check(3,C,S,1),
	write(C), nl,
	NC is C + 2,
	NS is sqrt(NC),
	primes(NC,M,NS).

primes(C,M,S) :-
	NC is C + 2,
	NS is sqrt(NC),
	primes(NC,M,NS).