!//////////////////////////////////////////////////////////
!// Name: Peter M. Maurer
!// Program: Sieve of Eratosthenes
!// Due: Never
!// Language: BLISS
!//////////////////////////////////////////////////////////

begin
	! define the sieve data structure
	own Candidates[1000],i,j;
	! everything is potentially prime until proven otherwise
	incr i from 0 to 999 do
		Candidates[.i] <- 1;
	! Neither 1 nor 0 is prime, so flag them off
	Candidates[0] <- 0;
	Candidates[1] <- 0;
	! start the sieve with the integer 0
	i <- 0;
	while .i<1000 do
	begin
		! advance to the next un-crossed out number.
		! this number must be a prime
		while .i<1000 AND Candidates[.i] = 0 do
			i <- .i + 1;
		! insure against running off the end of the data structure
		if .i<1000 then
		begin
			! cross out all multiples of the prime, starting with 2*p.
			j <- 2;
			while .j*.i < 1000 do
			begin
				Candidates[.j*.i] <- 0;
				j <- j + 1;
			end
			! advance to the next candidate
			i <- .i + 1;
		end
	end;
	! all uncrossed-out numbers are prime (and only those numbers)
	! print all primes
	incr i from 0 to 999 do
		if Candidates[i] NEQ 0 then
			! The following function is fake. BLISS has no built-in I/O
			! I guess you just used something from another language.
			Output(i," is prime\n");
end