Update 01.tour_of_cpp.md

Author: icecoobe

docs/c-cpp/01.tour_of_cpp.md

@@ -6,6 +6,11 @@
 祖师爷的行程单在[这里](https://stroustrup.com/tour3toc.pdf)。
 我个人建议的roadmap在[C++ Developer Roadmap](https://roadmap.sh/cpp)。
 
+## 工具网站
+
+- [cppreference](https://cppreference.com/w/cpp.html)
+- [cplusplus.com](https://cplusplus.com/reference/)
+
 ## const
 
 ### 全局const变量
@@ -146,3 +151,4 @@ class A
 - [cdecl](https://cdecl.org/)
   解析复杂的函数和指针定义等
   [How do I understand complicated function declarations?](https://stackoverflow.com/a/2663377)
+