SDWebImage 加载图片
Reachability 监测联网状态
SSKeyChain 钥匙串
SSZipArchive 压缩、解压缩zip、unzip //如出错，需要加载解压缩依赖的动态库libz.dylib或libz最新版本
AFNetworking 网络
OBShapedButton 判断按钮部分是否透明
__weak typeof(self) weakSelf = self;
iOS、OS X 都支持CoreGraphics, QuartzCore。
UIKit只支持iOS。
CALayer在QuartsCore框架中
CGImageRef、CGColorRef在CoreGraphics
UIImage、UIColor在UIKit。
1. ceil() 向上取整
//Test ceil() 向上取整
cout << "Test ceil() 向上取整!" << endl;
cout << "ceil 1.2 = " << ceil(1.2) << endl; //2
cout << "ceil 1.8 = " << ceil(1.8) << endl; //2
cout << "ceil -1.2 = " << ceil(-1.2) << endl; //-1
cout << "ceil -1.8 = " << ceil(-1.8) << endl; //-1
cout << "ceil 0.0 = " << ceil(0.0) << endl; //0
cout << endl;
2. floor() 向下取整
//Test floor() 向下取整
cout << "Test floor() 向下取整!" << endl;
cout << "floor 1.2 = " << floor(1.2) << endl; //1
cout << "floor 1.8 = " << floor(1.8) << endl; //1
cout << "floor -1.2 = " << floor(-1.2) << endl; //-2
cout << "floor -1.8 = " << floor(-1.8) << endl; //-2
cout << "floor 0.0 = " << floor(0.0) << endl; //0
cout << endl;
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