素数迭代器和计算

此库提供了一种迭代素数的结构，以及计算素数因子和将数字分类为素数或合数的方法。

API参考（docs.rs）

使用此库

将以下内容添加到您的 Cargo.toml 文件中

[dependencies]
elr_primes = "0.1.2"

示例

基本用法

use elr_primes::Primes;

// Provides an iterator for all prime numbers less than or equal to 1000
let mut p = Primes::new(1000);

一旦结构被初始化，primes() 方法提供了一个素数的迭代器。

# use elr_primes::Primes;
let p = Primes::new(10);  // Primes less than or equal to 10
let mut prime_iter = p.primes();
let primes: Vec<usize> = prime_iter.copied().collect();
let expected: [usize; 4] = [2, 3, 5, 7];
assert_eq!(primes, expected);

由于 primes() 返回一个迭代器，您也可以直接用它来查找特定的素数。

# use elr_primes::Primes;
let p = Primes::new(100); // Primes less than or equal to 100
let n = 20;

// Iterators are zero-based, so to get the 20th prime we need to search for the 19th
match p.primes().nth(n - 1) {
    Some(x) => println!("The {}th prime is: {}", n, x),
    None => println!("The {}th prime is outside the current bounds", n)
};

还有方法可以找到数字的素数因子，以及一个数字是素数还是合数。

use elr_primes::{Primes, Primality};
let p = Primes::new(100);

let n = 96;
match p.factors(n) {
    Ok(factors) => println!("{:?}", factors),
    Err(_) => println!("Could not find all prime factors within the bounds"),
};

let n = 23;
match p.primality(n) {
    Primality::Prime => println!("{} is prime", n),
    Primality::Composite => println!("{} is composite", n),
    Primality::Unknown => println!("Primality of {} is undetermined", n),
};