Fixed factorial bug

1 files changed, 4 insertions, 1 deletions

diff --git a/mathlib.py b/mathlib.py
index e9dffb9..4d98ad8 100644
--- a/mathlib.py
+++ b/mathlib.py
@@ -137,7 +137,7 @@ class MathLib:
 
     def is_int(self, n):
         (sign, d, e) = n.normalize().as_tuple()
-        return e == 0
+        return e >= 0
 
     def is_float(self, n):
         if isinstance(n, Decimal):
@@ -206,6 +206,9 @@ class MathLib:
         if not self.is_int(n):
             return self.d(0)
 
+        if n == 0:
+            return 1
+
         res = n
         while n > 2:
             res *= n - 1