rustでpascal's triangle

gistfile1.txt

use std;

fn factorial(n: int) -> int {
    if n == 0 {ret 1; }
    else {ret n * factorial(n - 1); }
}

fn bt(n: int, k: int) -> int {
    ret factorial(n) / (factorial(n -k) * factorial(k));
}

fn pascal(k: int) {
    let i = 0;
    while i <= k {
        let j = 0;
        while j <= i {
            std::io::print(int::str(bt(i, j)) + " ");
            j += 1;
        }
        std::io::println("");
        i += 1;
    }
}

fn main() {
    pascal(6);
}