2.8 如何限制光标的移动范围
..........................\Demo
..........................\....\Demo.cpp
..........................\....\Demo.dsp
..........................\....\Demo.dsw
..........................\....\Demo.h
..........................\....\Demo.plg
..........................\....\Demo.rc
..........................\....\DemoDoc.cpp
..........................\....\DemoDoc.h
..........................\....\DemoView.cpp
..........................\....\DemoView.h
..........................\....\MainFrm.cpp
..........................\....\MainFrm.h
..........................\....\ReadMe.txt
..........................\....\Resource.h
..........................\....\StdAfx.cpp
..........................\....\StdAfx.h
..........................\....\res
..........................\....\...\Demo.ico
..........................\....\...\Demo.rc2
..........................\....\...\DemoDoc.ico