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In the C++ programming language, the C++ Standard Library is a collection of classes and functions, which are written in the core language and part of the C++ ISO Standard itself.〔ISO/IEC 14882:2003(E) ''Programming Languages — C++'' §17-27〕 The C++ Standard Library provides several generic containers, functions to utilize and manipulate these containers, function objects, generic strings and streams (including interactive and file I/O), support for some language features, and everyday functions for tasks such as finding the square root of a number. The C++ Standard Library also incorporates 18 headers of the ISO C90 C standard library ending with ".h", but their use is deprecated.〔ISO/IEC 14882:2003(E) ''Programming Languages — C++'' §D.5〕 No other headers in the C++ Standard Library end in ".h". Features of the C++ Standard Library are declared within the std namespace.The C++ Standard Library is based upon conventions introduced by the Standard Template Library (STL), and has been influenced by research in generic programming and developers of the STL such as Alexander Stepanov and Meng Lee. Although the C++ Standard Library and the STL share many features, neither is a strict superset of the other. A noteworthy feature of the C++ Standard Library is that it not only specifies the syntax and semantics of generic algorithms, but also places requirements on their performance.〔"(Generic Algorithms )", David Musser〕 These performance requirements often correspond to a well-known algorithm, which is expected but not required to be used. In most cases this requires linear time O(''n'') or linearithmic time O(''n'' log ''n''), but in some cases higher bounds are allowed, such as quasilinear time O(''n'' log2 ''n'') for stable sort (to allow in-place merge sort). Previously sorting was only required to take O(''n'' log ''n'') on average, allowing the use of quicksort, which is fast in practice but has poor worst-case performance, but introsort was introduced to allow both fast average performance and optimal worst-case complexity, and as of C++11, sorting is guaranteed to be at worst linearithmic. In other cases requirements remain laxer, such as selection, which is only required to be linear on average (as in quickselect),〔(nth_element )〕 not requiring worst-case linear as in introselect. The C++ Standard Library underwent ISO standardization as part of the C++ ISO Standardization effort, and is undergoing further work〔(【引用サイトリンク】 publisher= ISO/IEC )〕 regarding standardization of expanded functionality. ==Standard headers== The following files contain the declarations of the C++ Standard Library. 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「C++ Standard Library」の詳細全文を読む スポンサード リンク
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