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@mjs
Created August 25, 2017 01:54
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Fibonacci sequence generation done in 3 ways using Rust
const ITERS: usize = 20;
fn print_fib(n: usize) {
let mut x = (1, 1);
for i in 0..n {
println!("{}: {}", i, x.0);
x = (x.1, x.0 + x.1)
}
}
fn make_fib(n: usize) -> Vec<i32> {
let mut x = vec![1, 1];
for i in 2..n {
let next_x = x[i - 1] + x[i - 2];
x.push(next_x)
}
x
}
struct Fib {
x: (usize, usize),
}
impl Fib {
fn new() -> Fib {
Fib { x: (0, 1) }
}
}
impl Iterator for Fib {
type Item = usize;
fn next(&mut self) -> Option<Self::Item> {
self.x = (self.x.1, self.x.0 + self.x.1);
Some(self.x.0)
}
}
fn main() {
println!("# print_fib");
print_fib(ITERS);
println!("\n# make_fib");
println!("{:?}", make_fib(ITERS));
println!("\n# iterator");
for (i, x) in Fib::new().take(ITERS).enumerate() {
println!("{}: {}", i, x);
}
}
@autocatalytic
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These are great. Thanks!

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