关于手动创设窗口

关于手动创建窗口
手动创建窗口，有问题，见代码，求帮助
delegate.h

@interface snAppDelegate : UIResponder <UIApplicationDelegate>
{
    //snViewController *viewControl;
    UIViewController *viewControl;
    UIWindow *window;
}
@property (strong, nonatomic) UIWindow *window;
@end

deletate.m

@implementation snAppDelegate
@synthesize window = _windows;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    
    //snViewController *viewControl = [[snViewController alloc] initWithNibName:@"snviewcontroller" bundle:nil];
    snViewController *viewControl = [[snSecondViewController alloc] initWithNibName:@"snSecondViewController" bundle:nil];
    
    self.window.rootViewController = viewControl;
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    return YES;
}
- (void)applicationWillResignActive:(UIApplication *)application{}
- (void)applicationDidEnterBackground:(UIApplication *)application{}
- (void)applicationWillEnterForeground:(UIApplication *)application{}
- (void)applicationDidBecomeActive:(UIApplication *)application{}
- (void)applicationWillTerminate:(UIApplication *)application{}
@end

viewController.h

#import <UIKit/UIKit.h>
@interface snSecondViewController : UIViewController
@end

viewController.m

#import "snSecondViewController.h"
@interface snSecondViewController ()
@end

@implementation snSecondViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
    }
    return self;
}
- (void)viewDidLoad
{
    [super viewDidLoad];
}
- (void)viewDidUnload
{
    [super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
@end

------解决方案--------------------
snViewController *viewControl这个地儿你不报错么、不应该是snSecondViewController么
------解决方案--------------------
@synthesize window = _windows;
为什么右边要写成windows
不过我跑了一下，没什么问题
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