-- Eiffel version of a Prime Number Finder
-- haplo@mindstab.net
-- Anyone know how to round off doubles? or cast them to integers please
-- email me.  I should be able to speed this up then.

class PRIMES

creation make

feature

    make is 
        local
	    max, i, cnt, isprime : INTEGER;
	    test: DOUBLE;
	    stop : BOOLEAN;
	do
		if argument_count < 1 or else not argument(1).is_integer then
		    io.put_string("Useage: primese [Max Num]%N");
		    die_with_code(exit_failure_code);
		else 
		    max := argument(1).to_integer;
		end;

		from
		    cnt := 3;
		until
		    cnt > max
		loop
		    test := cnt.sqrt;
		    isprime := 1;
		    stop := false;

		    from
		    	i := 3;
		    until
		        i > test or stop 
		    loop
			from 
			   isprime := cnt;
			until
			   isprime < i
			loop
			    isprime := isprime-i;
			end;
			--isprime := cnt - (i* do_round_down(cnt/i));
			if isprime = 0 then 
				stop := true
			end;
			i := i + 2;
		    end;
			
		    if isprime /= 0 then 
		       io.put_integer(cnt);
		       io.put_string("%N");
		    end;
		    cnt := cnt + 2;
		end;
	end;
end