NSDateに日数を加算する

NSDateに日数を加算したNSDateを生成する。

NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [[NSDateComponents alloc] init];
NSDate *today = [NSDate date];

// １日マイナス
components.day = -1;
NSDate *yesterday = [calendar dateByAddingComponents:components toDate:today options:0];
// １日プラス
components.day = 1;
NSDate *tommorow = [calendar dateByAddingComponents:components toDate:today options:0];

// ログ出力
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = @"yyyy.MM.dd HH:mm:ss";
NSLog(@"today:%@ yesterday:%@ tommorow:%@",
      [formatter stringFromDate:today],
      [formatter stringFromDate:yesterday],
      [formatter stringFromDate:tommorow]);