四则括号运算
............\d.cpp
............\d.dsp
............\d.dsw
............\d.ncb
............\d.opt
............\d.plg
............\Debug
............\.....\d.exe
............\.....\d.ilk
............\.....\d.obj
............\.....\d.pch
............\.....\d.pdb
............\.....\vc60.idb
............\.....\vc60.pdb