# Crate bit_vec

Expand description

Collections implemented with bit vectors.

## §Examples

This is a simple example of the Sieve of Eratosthenes which calculates prime numbers up to a given limit.

``````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);``````

## Structs§

• The bitvector type.
• An iterator over the blocks of a `BitVec`.
• An iterator for `BitVec`.

## Traits§

• Abstracts over a pile of bits (basically unsigned primitives)