third_party/rust/bit-vec/src

Name	Description	Size	Coverage
lib.rs	# Description Dynamic collections implemented with compact bit vectors. # Examples This is a simple example of the [Sieve of Eratosthenes][sieve] which calculates prime numbers up to a given limit. [sieve]: http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes ``` use bit_vec::BitVec; let max_prime = 10000; // Store the primes as a BitVec let primes = { // Assume all numbers are prime to begin, and then we // cross off non-primes progressively let mut bv = BitVec::from_elem(max_prime, true); // Neither 0 nor 1 are prime bv.set(0, false); bv.set(1, false); for i in 2.. 1 + (max_prime as f64).sqrt() as usize { // if i is a prime if bv[i] { // Mark all multiples of i as non-prime (any multiples below i * i // will have been marked as non-prime previously) for j in i.. { if i * j >= max_prime { break; } bv.set(i * j, false) } } } bv }; // Simple primality tests below our max bound let print_primes = 20; print!("The primes below {} are: ", print_primes); for x in 0..print_primes { if primes.get(x).unwrap_or(false) { print!("{} ", x); } } println!(); let num_primes = primes.iter().filter(\|x\| *x).count(); println!("There are {} primes below {}", num_primes, max_prime); assert_eq!(num_primes, 1_229); ```	106514	-