fix

src/lib.rs

@@ -1,6 +1,6 @@
 use std::{fmt, ops};
 
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, PartialOrd, Ord)]
 pub struct Fraction {
     num: i64,
     den: i64,
@@ -158,7 +158,11 @@ impl ops::Neg for Fraction {
 
 impl fmt::Display for Fraction {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{0}/{1}", self.num, self.den)
+        if self.den == 1 {
+            return write!(f, "{0}", self.num);
+        } else {
+            return write!(f, "{0}/{1}", self.num, self.den);
+        }
     }
 }