疊代器

for 陳述式支援對陣列進行疊代 (對元組則不支援)。

fn main() {
    let primes = [2, 3, 5, 7, 11, 13, 17, 19];
    for prime in primes {
        for i in 2..prime {
            assert_ne!(prime % i, 0);
        }
    }
}