Apple has deprecated UIAlertView in iOS 8 and above. Now they have introduce UIAlertController, below are the examples.

AlertView without buttons:-

UIAlertController * alert=   [UIAlertController
                                alertControllerWithTitle:@"Sample App"
                                message:@"Welcome!!!"
                                preferredStyle:UIAlertControllerStyleAlert];

[self presentViewController:alert animated:YES completion:nil];

AlertView with buttons and their actions:-

    UIAlertController * alert=   [UIAlertController
                                 alertControllerWithTitle:@"Info"
                                 message:@"You are using UIAlertController"
                                 preferredStyle:UIAlertControllerStyleAlert];

   UIAlertAction* okBtn = [UIAlertAction
                        actionWithTitle:@"OK"
                        style:UIAlertActionStyleDefault
                        handler:^(UIAlertAction * action)
                        {
                            [alert dismissViewControllerAnimated:YES completion:nil];

                        }];
   UIAlertAction* cancelBtn= [UIAlertAction
                            actionWithTitle:@"Cancel"
                           style:UIAlertActionStyleDefault
                           handler:^(UIAlertAction * action)
                           {
                               [alert dismissViewControllerAnimated:YES completion:nil];

                           }];

   [alert addAction:okBtn];
   [alert addAction:cancelBtn];

   [self presentViewController:alert animated:YES completion:nil];

Happy Coding!!!