Deal with null charges on 'this' too

Change-Id: I94f5cea8fef424c597bd00390f056d87782a2247
egonw · Sep 16, 2014 · 5f444a1 · 5f444a1
1 parent a988852
commit 5f444a1
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/base/silent/src/main/java/org/openscience/cdk/silent/MolecularFormula.java b/base/silent/src/main/java/org/openscience/cdk/silent/MolecularFormula.java
@@ -88,7 +88,11 @@ public IMolecularFormula add(IMolecularFormula formula) {
         for (IIsotope newIsotope : formula.isotopes()) {
             addIsotope(newIsotope, formula.getIsotopeCount(newIsotope));
         }
-        if (formula.getCharge() != null) charge += formula.getCharge();
+        if (formula.getCharge() != null)
+            if (charge != null)
+                charge += formula.getCharge();
+            else
+                charge = formula.getCharge();
         return this;
     }