Calculator

 This is caculator made by someone.(I actually don't remember the origin of this code.)
Well...
Since this code was not made by me I can not share it...
Sorry guys!!!

PLEASE GIVE ME COMMENTS!!!
COMMENT IS VERY HELPFUL FOR ME.

 I FOUND THE URL!!!
THIS IS KOREAN Q&A SITE.
THE RIGHT CODE IS SECOND ONE.

http://kin.naver.com/qna/detail.nhn?d1id=1&dirId=1040205&docId=160674314&qb=6rOE7IKw6riwIGh0bWw=&enc=utf8&section=kin&rank=1&search_sort=0&spq=0&pid=SzT/HwpySpZssuYwI7Vsssssssw-168110&sid=Orxg%2BOfJnn75ZhJSyB/29A%3D%3D