vim

http://coolshell.cn/articles/11312.html

http://coolshell.cn/articles/894.html

遞迴轉迴圈

http://stackoverflow.com/questions/159590/way-to-go-from-recursion-to-iteration
http://www.codeproject.com/Articles/418776/How-to-replace-recursive-functions-using-stack-and

在google找關鍵字「recursive to iterative」也可以找到不少資料