On branch master
 Changes to be committed:

	new file:   10_2/lazy
	new file:   10_2/lazy.cpp
	new file:   10_3_2/demo.cpp
	new file:   10_3_2/demo2.cpp
	new file:   10_3_5/demo
	new file:   10_3_5/demo.cpp
	new file:   10_5/demo
	new file:   10_5/demo.cpp
	new file:   11_7/demo
	new file:   11_7/demo.cpp
	new file:   12_4/demo
	new file:   12_4/demo.cpp