累加求和，累加求阶乘\c1.c
....................\c1.dsp
....................\c1.dsw
....................\c1.ncb
....................\c1.opt
....................\c1.plg
....................\Debug\c1.exe
....................\.....\c1.ilk
....................\.....\c1.obj
....................\.....\c1.pch
....................\.....\c1.pdb
....................\.....\vc60.idb
....................\.....\vc60.pdb
....................\Debug
累加求和，累加求阶乘