Add output for example in "Postfix Increment and Decrement Operators"

Rageking8 · web-flow · commit a79cd027b668 · 2025-07-05T18:52:08.000+08:00
diff --git a/docs/cpp/postfix-increment-and-decrement-operators-increment-and-decrement.md b/docs/cpp/postfix-increment-and-decrement-operators-increment-and-decrement.md
@@ -51,6 +51,11 @@ int main()
 }
 ```
 
+```Output
+10
+11
+```
+
 Postincrement and postdecrement operations on enumerated types are not supported:
 
 ```cpp
