// 判断设备的iOS 版本号

    float version = [[[UIDevice currentDevice] systemVersion] floatValue];

    NSLog(@"%f",version);

二、我们还可以获得更多相应的设备信息

 NSLog(@"%@",[[UIDevice currentDevice] name]); // Name of the phone as named by user

    NSLog(@"%@",[[UIDevice currentDevice] uniqueIdentifier]); // A GUID like string 

    NSLog(@"%@",[[UIDevice currentDevice] identifierForVendor]); // A GUID like string（iOS 6.0）

    NSLog(@"%@",[[UIDevice currentDevice] systemName]); // "iPhone OS"

    NSLog(@"%@",[[UIDevice currentDevice] systemVersion]); // "5.1.1"

    NSLog(@"%@",[[UIDevice currentDevice] model]); // "iPhone" on both devices

    NSLog(@"%@",[[UIDevice currentDevice] localizedModel]); // "iPhone" on both devices

三、获得App的版本号

// 获得软件的版本号,

    NSDictionary* infoDict =[[NSBundle mainBundle] infoDictionary];

    float softVerson =[[infoDict objectForKey:@"CFBundleShortVersionString"] floatValue];

读取 Info.plist文件的信息。

 NSDictionary* infoDict =[[NSBundle mainBundle] infoDictionary];