2016 Update

Task/Fibonacci-sequence/Rust/fibonacci-sequence-1.rust

@@ -1,30 +1,12 @@
-#![feature(zero_one)]
-use std::num::One;
-use std::ops::Add;
-
-struct Fib<T> {
-    curr: T,
-    next: T,
-}
-
-impl<T> Fib<T> where T: One {
-    fn new() -> Self {
-        Fib {curr: T::one(), next: T::one()}
-    }
-}
-
-impl<T> Iterator for Fib<T> where T: Add<T, Output=T> + Copy {
-    type Item = T;
-    fn next(&mut self) -> Option<Self::Item>{
-        let new = self.curr + self.next;
-        self.curr = self.next;
-        self.next = new;
-        Some(self.curr)
-    }
-}
-
+use std::mem;
 fn main() {
-    for i in Fib::<u64>::new() {
-        println!("{}", i);
+    let mut prev = 0;
+    // Rust needs this type hint for the checked_add method
+    let mut curr = 1usize;
+
+    while let Some(n) = curr.checked_add(prev) {
+        prev = curr;
+        curr = n;
+        println!("{}", n);
     }
 }