IOS gets two milliseconds of time difference

IOS gets two milliseconds of time difference
IOS gets two milliseconds of time difference by Wu xueying

NSString * savedTime = [[NSUserDefaults standardUserDefaults] stringForKey: @ "time"]; NSString * time = [NSString stringWithFormat: @ "% f", (double) [[NSDate date] timeIntervalSince1970]; NSLog (@ "\ n % @", time, savedTime); NSLog (@ "%. f ", ([time doubleValue]-[savedTime doubleValue]) * 1000); [[NSUserDefaults standardUserDefaults] setObject: time forKey: @" time "]; [[NSUserDefaults standardUserDefaults] synchronize];