Note of Objective C

problems:

1. missing sentinel in function call

UIAlertView *alert = [[UIAlertView alloc]

  initWithTitle:@"Date and Time Selected"

  message:msg

  delegate:nil

  cancelButtonTitle:@"Yes, I did"

  otherButtonTitles:@"other Button", nil];//parameter otherButtonTitles is type like format... in NSLog, so the last nil is need to suppress such warning.