September 2017 Update

Task/Exponentiation-operator/Rust/exponentiation-operator.rust

@@ -0,0 +1,24 @@
+extern crate num;
+use num::traits::One;
+use std::ops::Mul;
+
+fn pow<T>(mut base: T, mut exp: usize) -> T
+    where T: Clone + One + Mul<T, Output=T>
+{
+    if exp == 0 { return T::one() }
+    while exp & 1 == 0 {
+        base = base.clone() * base;
+        exp >>= 1;
+    }
+    if exp == 1 { return base }
+    let mut acc = base.clone();
+
+    while exp > 1 {
+        exp >>= 1;
+        base = base.clone() * base;
+        if exp & 1 == 1 {
+            acc = acc * base.clone();
+        }
+    }
+    acc
+}