Small changes

src/fraction.rs

@@ -19,7 +19,7 @@ pub struct Rational {
 }
 
 impl Fraction {
-    pub fn new(numerator: Number, denominator: Number) -> Result<Self, Box<dyn Error>> {
+    pub fn new(mut numerator: Number, mut denominator: Number) -> Result<Self, Box<dyn Error>> {
         if denominator == 0.into() {
             return Err(Box::from("Division by 0"));
         }
@@ -33,6 +33,8 @@ impl Fraction {
                 Sign::Negatif => Sign::Positif,
             },
         };
+        numerator.sign = Sign::Positif;
+        denominator.sign = Sign::Positif;
         let mut f = Fraction {
             numerator,
             denominator,

src/number.rs

@@ -57,15 +57,12 @@ impl Number {
 
     pub fn fact(self) -> Self {
         let mut fact = Number::from(1);
-        if ((self.digits.len() * 8) as u32) < isize::BITS {
-            let max = isize::try_from(self).unwrap();
-            for n in 1..=max {
-                fact = fact * n;
-            }
-            fact
-        } else {
-            panic!("starting number too big")
+        let mut n = Number::from(1);
+        while n <= self {
+            fact *= n.clone();
+            n += 1.into();
         }
+        fact
     }
 
     pub fn fib(n: u64) -> Self {