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In computer science, peek is an operation on certain abstract data types, specifically sequential collections such as stacks and queues, which returns the value of the top of the collection without removing the value from the data. It thus returns the same value as operations such as "pop" or "dequeue", but does not modify the data. The name "peek" is similar to the basic "push" and "pop" operations on a stack, but the name for this operation varies depending on data type and language. Peek is generally considered an inessential operation, compared with the more basic operations of adding and removing data, and as such is not included in the basic definition of these data types. However, since it is a useful operation and generally easily implemented, it is frequently included in practice. == Data types == Sequential types for which peek is often implemented include: * Stack * Queue * Priority queue (such as a heap) * Double-ended queue (deque) * Double-ended priority queue (DEPQ) Single-ended types, such as stack, generally only admit a single peek, at the end that is modified. Double-ended types, such as deques, admit two peeks, one at each end. Names for peek vary. "Peek" or "top" are common for stacks, while for queues "front" is common. Operations on deques have varied names, often "front" and "back" or "first" and "last". The name "peak" is also occasionally found, in the sense of "top, summit", though this also occurs as a spelling error for the verb "peek". 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Peek (data type operation)」の詳細全文を読む スポンサード リンク
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