From 2ff4f42d43c26671fe8fb22366122d8f722f2864 Mon Sep 17 00:00:00 2001
From: Alexander Launi <alex.launi@gmail.com>
Date: Sat, 21 Mar 2020 16:41:02 -0400
Subject: [PATCH] Implement countdown using generic mathematics

---
 03_recursion/rust/01_countdown/Cargo.toml  |  1 +
 03_recursion/rust/01_countdown/src/main.rs | 11 ++++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/03_recursion/rust/01_countdown/Cargo.toml b/03_recursion/rust/01_countdown/Cargo.toml
index 076bdcd..9d582e3 100644
--- a/03_recursion/rust/01_countdown/Cargo.toml
+++ b/03_recursion/rust/01_countdown/Cargo.toml
@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+num-traits = "0.2"
\ No newline at end of file
diff --git a/03_recursion/rust/01_countdown/src/main.rs b/03_recursion/rust/01_countdown/src/main.rs
index 2fdb117..84ae0e7 100644
--- a/03_recursion/rust/01_countdown/src/main.rs
+++ b/03_recursion/rust/01_countdown/src/main.rs
@@ -1,10 +1,15 @@
-fn countdown(i: u32) {
+use std::ops::Sub;
+use std::fmt::Display;
+use num_traits::identities::One;
+use num_traits::identities::Zero;
+
+fn countdown<T: Display + One + Zero + Sub<Output = T>>(i: T) {
     println!("{}", i);
-    if i == 0 {
+    if i.is_zero() {
         return
     }
 
-   countdown(i - 1);
+   countdown(i - T::one());
 }
 
 fn main() {