objective-c/比較 - iPhoneアプリ作成のために

比較で帰ってくる値　NSComparisonResult

• A < B　NSOrderedAscending　-1
• A = B　NSOrderedSame 0
• A > B NSOrderedDescending 1

例　A<B<C

• A < B　[A compare:B] == NSOrderedAscending　
• B < C　[B compare:C] == NSOrderedAscending　

例２ A<=B<=C

• A <= B これは !(A > B)のことつまり、 [A compare:B] != NSOrderedDescending
• B <= C これは !(B > C)のことつまり、 [B compare:C] != NSOrderedDescending