Bookmark // ImageAndTextCell.h // SimpleTreeController // // Created by System Administrator on 7/13/11. // Copyright 2011 __MyCompanyName__. All rights reserved. // -Bookmark // // ImageAndTextCell.h // SimpleTreeController /

OC写的一个关于三角函数的计算器功能 关于分类以及协议， Programming in OC书上的 chapter11中的第四题-The functions sin(), cos(), and tan() are part of the C Standard Library (as scanf () is). These functions are declared in the system header file math.h, which is automatically impo