Merge pull request #18 from macocci7/dev_#17

#17: bug fix: Fraction::toCommonDenominator()

Author: macocci7

composer.json

@@ -1,6 +1,6 @@
 {
     "name": "macocci7/php-math-integer",
-    "version": "1.0.1",
+    "version": "1.0.2",
     "description": "PHP Math Library of the subjects of number theory(only natural number).",
     "type": "library",
     "license": "MIT",

src/Fraction.php

@@ -164,6 +164,9 @@ public function reduce()
      */
     public function toCommonDenominator(Fraction &$f)
     {
+        if (0 === (int) $this->denominator || 0 === (int) $f->denominator) {
+            throw new \Exception('denominator must not be null nor zero.', 1);
+        }
         $cd = $this->m->leastCommonMultiple(
             $this->denominator,
             $f->denominator