1 files changed, 12 insertions, 15 deletions

diff --git a/src/poly.rs b/src/poly.rs
index 7d964a4..9c70048 100644
--- a/src/poly.rs
+++ b/src/poly.rs
@@ -3,6 +3,7 @@ mod iter;
 use crate::number::Number;
 use iter::Iter;
 use std::ops::{Add, Div, Mul, Sub};
+use std::fmt;
 
 #[derive(PartialEq, Debug, Clone)]
 pub struct Poly {
@@ -29,7 +30,7 @@ impl Poly {
         }
     }
 
-    fn degree(&self) -> usize {
+    pub fn degree(&self) -> usize {
         self.degree
     }
 
@@ -109,21 +110,17 @@ impl Div for &Poly {
     }
 }
 
-pub fn gcd(a: &Poly, b: &Poly) -> Poly {
-    let (_, c) = a / b;
-    if c.is_zero() {
-        b.clone()
-    } else {
-        gcd(b, &c)
-    }
-}
-
-pub fn derivative(p: &Poly) -> Poly {
-    let mut v = vec![0.0; p.degree()];
-    for i in 0..v.len() {
-        v[i] = p.data[i + 1] * (i + 1) as Number;
+impl fmt::Display for &Poly {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut s = String::new();
+        for i in 0..self.data.len() {
+            s.push_str(&self.data[i].clone().to_string());
+            if i < self.data.len() - 1 {
+                s.push_str(", ");
+            }
+        }
+        write!(f, "{}", s)
     }
-    Poly::new(v)
 }
 
 #[cfg(test)]