diff --git a/examples/calculator/src/calculator.cpp b/examples/calculator/src/calculator.cpp
index 9b504d69bae9bb8e4aae2a9989089e473f4c8d5c..d4447604658e3c9a8ccacfc5e0bc61ace95985e3 100644
--- a/examples/calculator/src/calculator.cpp
+++ b/examples/calculator/src/calculator.cpp
@@ -33,7 +33,10 @@ int Sub(int e1, int e2)
 int Mul(int e1, int e2)
 {
     int result = e1 * e2;
-    if (!e1 || (result / e1) != e2) {
+    if (e1 == 0) {
+        return -1;
+    }
+    if ((result / e1) != e2) {
         result = -1;
     }
     return result;