ios判断系统是24小时制还是12小时制

//获取系统是24小时制或者12小时制
    NSString *formatStringForHours = [NSDateFormatter dateFormatFromTemplate:@"j" options:0 locale:[NSLocale currentLocale]];
    NSRange containsA = [formatStringForHours rangeOfString:@"a"];
    BOOL hasAMPM = containsA.location != NSNotFound;
//hasAMPM==TURE为12小时制，否则为24小时制