| 1 | /* |
| 2 | The Sieve of Erathostenes |
| 3 | Prints all prime numbers up to PRIME_MAX |
| 4 | */ |
| 5 | #define PRIME_MAX 100 |
| 6 | |
| 7 | chan count = [0] of { int }; |
| 8 | byte tries = 2; |
| 9 | |
| 10 | proctype sieve(chan c; int prime) |
| 11 | { int i, haschild; |
| 12 | |
| 13 | end: do |
| 14 | :: c?i -> |
| 15 | if |
| 16 | :: (i%prime) -> |
| 17 | if |
| 18 | :: !haschild -> |
| 19 | /* found a new prime */ |
| 20 | printf("MSC: %d\n", i); |
| 21 | haschild++; |
| 22 | chan child = [0] of { int }; |
| 23 | run sieve(child, i); |
| 24 | :: else -> |
| 25 | child!i |
| 26 | fi; |
| 27 | :: else |
| 28 | /* i is divisible by prime */ |
| 29 | fi |
| 30 | od |
| 31 | } |
| 32 | |
| 33 | init |
| 34 | { |
| 35 | run sieve(count, 2); |
| 36 | do |
| 37 | :: (tries < PRIME_MAX) -> count!tries; tries++ |
| 38 | :: (tries >= PRIME_MAX) -> break |
| 39 | od |
| 40 | } |