我们是否需要在推入导航控制器后释放viewcontroller的对象？

here is sample code.

这是示例代码。

if(MyPageViewControllerObj==nil)
    {
        MyPageViewController *vController = [[MyPageViewController alloc] initWithNibName:@"MyPageView" bundle:[NSBundle mainBundle]];
        self.MyPageViewControllerObj=vController;
        [vController release];
        noOfWrongAnswers=0;
        noOfRightAnswers=0;
    }
    MyPageViewControllerObj.sessionid=sessionid;
    MyPageViewControllerObj.categoryID = categoryId;
    MyPageViewControllerObj.flashcardIdforcount = flashcardid;
    MyPageViewControllerObj.categoryType=categoryType;
    MyPageViewControllerObj.indexViewControllerobj=self;
    [self.navigationController pushViewController:MyPageViewControllerObj animated:YES];
if(MyPageViewC