Assignment No.11 fixed an empty string problem

1 files changed, 40 insertions, 36 deletions

diff --git a/src/de/fhswf/in/inf/java1/aufgabe11/UPN.java b/src/de/fhswf/in/inf/java1/aufgabe11/UPN.java
index f8938fc..893aa93 100644
--- a/src/de/fhswf/in/inf/java1/aufgabe11/UPN.java
+++ b/src/de/fhswf/in/inf/java1/aufgabe11/UPN.java
@@ -44,42 +44,46 @@ public class UPN
       for (String string : upnString.split("\\s+"))
       {
 
-         Double[] operands = null;
-
-         switch (string)
+         if (!string.isEmpty())
          {
-            case "+":
-               operands = fetch();
-               upnStack.add(operands[0] + operands[1]);
-               break;
-            case "-":
-               operands = fetch();
-               upnStack.add(operands[0] - operands[1]);
-               break;
-            case "*":
-               operands = fetch();
-               upnStack.add(operands[0] * operands[1]);
-               break;
-            case "/":
-               divisorZero();
-               operands = fetch();
-               upnStack.add(operands[0] / operands[1]);
-               break;
-            case "%":
-               divisorZero();
-               operands = fetch();
-               upnStack.add(operands[0] % operands[1]);
-               break;
-            default:
-               try
-               {
-                  upnStack.add(Double.valueOf(string));
-               }
-               catch (NumberFormatException e)
-               {
-                  throw new IllegalArgumentException("String: \"" + string
-                        + "\" is not a valid operator nor a valid operand.");
-               }
+            Double[] operands = null;
+
+            switch (string)
+            {
+               case "+":
+                  operands = fetch();
+                  upnStack.add(operands[0] + operands[1]);
+                  break;
+               case "-":
+                  operands = fetch();
+                  upnStack.add(operands[0] - operands[1]);
+                  break;
+               case "*":
+                  operands = fetch();
+                  upnStack.add(operands[0] * operands[1]);
+                  break;
+               case "/":
+                  divisorZero();
+                  operands = fetch();
+                  upnStack.add(operands[0] / operands[1]);
+                  break;
+               case "%":
+                  divisorZero();
+                  operands = fetch();
+                  upnStack.add(operands[0] % operands[1]);
+                  break;
+               default:
+                  try
+                  {
+                     upnStack.add(Double.valueOf(string));
+                  }
+                  catch (NumberFormatException e)
+                  {
+                     throw new IllegalArgumentException("String: \"" + string
+                           + "\" is not a valid"
+                           + " operator nor a valid operand.");
+                  }
+            }
          }
       }
    }
@@ -97,7 +101,7 @@ public class UPN
       }
       return upnStack.peek();
    }
-   
+
    /**
     * Checks if Divisor will be zero.
     *