怎么判断ios 版本

-(void)getIOSVersion

{

// #if __IPHONE_OS_VERSION_MAX_ALLOWED >= 50000    //此方法和编译器相关

// quanju.iOSVersion=1;

// #endif 

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

if (version >= 5.0)  

{  

quanju.iOSVersion=1;//定义全局变量标记ios版本

}  

}

-(void)getIOSModel

{

CGSize sizeToRequest; 
if([[[UIDevicecurrentDevice] model] rangeOfString:@"iPad"].location== 0) 
sizeToRequest = CGSizeMake(748, 110); 
else 
sizeToRequest = CGSizeMake(320, 48); 

}

//下面是ios内其他相关信息的判断方法

获取进程信息和设备信息（包括设备类型，序列号，ios版本等）
[[NSProcessInfo processInfo] globallyUniqueString],
[[NSProcessInfo processInfo] hostName],
[[NSProcessInfo processInfo] operatingSystemName],
[[NSProcessInfo processInfo] operatingSystemVersionString],
[[NSProcessInfo processInfo] physicalMemory],
[[NSProcessInfo processInfo] processName]);
——————————————————————————————
[UIDevice currentDevice].uniqueIdentifier,
[UIDevice currentDevice].name,
[UIDevice currentDevice].systemName,
[UIDevice currentDevice].systemVersion,
[UIDevice currentDevice].model,
[UIDevice currentDevice].localizedModel,
[UIDevice currentDevice].batteryLevel
___________________________________________________
NSLog([[UIDevice currentDevice] name]); // Name of the phone as named by user
NSLog([[UIDevice currentDevice] uniqueIdentifier]); // A GUID like string
NSLog([[UIDevice currentDevice] systemName]); // "iPhone OS"
NSLog([[UIDevice currentDevice] systemVersion]); // "2.2.1"
NSLog([[UIDevice currentDevice] model]); // "iPhone" on both devices
NSLog([[UIDevice currentDevice] localizedModel]); // "iPhone" on both devices

转自：http://blog.csdn.net/jinglijun/article/details/7292674