line breaks

lectures/25_garbage_collection/README.md

@@ -22,6 +22,8 @@ have performance and memory usage disadvantages.
 
 - For our discussion today, we’ll assume that all program data is stored in dynamically-allocated instances of the
 following simple class. This class can be used to build linked lists, trees, and graphs with cycles:
+
+```cpp
 class Node {
 public:
 	Node(char v, Node* l, Node* r) :
@@ -30,6 +32,7 @@ public:
 	Node* left;
 	Node* right;
 };
+```
 
 ## 25.3 Garbage Collection Technique #1: Reference Counting
 
@@ -167,11 +170,11 @@ also when we are developing big complex programs that process and rearrange lots
 enormous beast of a programming language (but that doesn’t stop people from trying!). So is there anything
 we can do? Yes, we can use Smart Pointers to gain some of the features of garbage collection.
  Some examples below are modified from these nice online references:
-http://ootips.org/yonat/4dev/smart-pointers.html
-http://www.codeproject.com/KB/stl/boostsmartptr.aspx
-http://en.wikipedia.org/wiki/Smart_pointer
-http://www.boost.org/doc/libs/1_48_0/libs/smart_ptr/smart_ptr.htm
-http://www.acodersjourney.com/2016/05/top-10-dumb-mistakes-avoid-c-11-smart-pointers/
+[http://ootips.org/yonat/4dev/smart-pointers.html](http://ootips.org/yonat/4dev/smart-pointers.html)
+[http://www.codeproject.com/KB/stl/boostsmartptr.aspx](http://www.codeproject.com/KB/stl/boostsmartptr.aspx)
+[http://en.wikipedia.org/wiki/Smart_pointer](http://en.wikipedia.org/wiki/Smart_pointer)
+[http://www.boost.org/doc/libs/1_48_0/libs/smart_ptr/smart_ptr.htm](http://www.boost.org/doc/libs/1_48_0/libs/smart_ptr/smart_ptr.htm)
+[http://www.acodersjourney.com/2016/05/top-10-dumb-mistakes-avoid-c-11-smart-pointers/](http://www.acodersjourney.com/2016/05/top-10-dumb-mistakes-avoid-c-11-smart-pointers/)
 
 ## 25.12 What’s a Smart Pointer?