表达式求值

后缀表达式定义

http://www.nowamagic.net/librarys/veda/detail/2302

中缀转后缀

http://www.nowamagic.net/librarys/veda/detail/2307

后缀表达式求值

http://www.nowamagic.net/librarys/veda/detail/2306