wrap up with c++ markdown

Haoyang Chen · web-flow · commit 362aa7850954 · 2017-08-20T15:30:46.000-07:00
diff --git a/zh-hans/basics_data_structure/heap.md b/zh-hans/basics_data_structure/heap.md
@@ -72,7 +72,7 @@ class MaxHeap:
         return item
 ```
 ## C++
-```
+```c++
 #ifndef HEAP_H
 #define HEAP_H
 
