Thread: C++ Strings under the STL?

  1. #1
    C++ Witch laserlight's Avatar
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    C++ Strings under the STL?

    I had the impression that C++ strings arent implemented as a template class, so they dont come under the standard template library.

    A little googling appears to confirm this.
    http://www.msoe.edu/eecs/ce/courseinfo/stl/

    However, I've also seen references to "STL strings", which apparently refer to C++ strings, i.e. those using <string>

    Are C++ strings considered as part of the STL then?

  2. #2
    Registered User Codeplug's Avatar
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    <string> is part of the standard template library.

    gg

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    Registered User jlou's Avatar
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    Re: C++ Strings under the STL?

    Originally posted by laserlight
    I had the impression that C++ strings arent implemented as a template class, so they dont come under the standard template library.
    The STL string class is implemented as a template class, its just the string itself is a specialization for ASCII chars. It is basically defined as:

    typedef basic_string<char, char_traits<char>, allocator<char> > string;

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    std::string is defined to be a specialization of basic_string in the standard -- lib.string.classes
    Code:
      namespace std {
      // Lots of stuff defining basic_string and character traits....
    
        typedef basic_string<char> string;
        typedef basic_string<wchar_t> wstring;
      }
    That said, "Standard Template Library" is sort of an undefined term. I don't think it's actually part of the standard, and I've never heard it used in a manner distinguishable from "C++ Standard Library".
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    Hurry Slowly vart's Avatar
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    Quote Originally Posted by QuestionC View Post
    That said, "Standard Template Library" is sort of an undefined term.
    Well, no so undefined... http://www.cppreference.com/cppstl.html
    Have you tried to google it?
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    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    Soo....

    laserlight self-quotes, you click the link, and respond to the question? (Unfortunately, I think laserlight already knows the answer.)

    Perhaps in a few years you'll look back on this day as laserlight did... history is doomed to repeat itself, it seems.
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  7. #7
    Cat without Hat CornedBee's Avatar
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    The STL was a library developed by HP, before the C++ standardization. It contained containers, algorithms, and iterators that were the glue between them.

    When C++ was standardized, the classes from the STL were made part of the C++ standard library, and the std::string class was designed to be similar to the containers in interface. However, as far as the standard is concerned, there is no such thing as the STL. QuestionC is quite right. STL is sometimes used to refer to:
    1) the whole C++ standard library,
    2) just the part that derives from the original STL, i.e. containers, algorithms and iterators or
    3) that part, plus std::string.
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    Quote Originally Posted by vart View Post
    Well, no so undefined... http://www.cppreference.com/cppstl.html
    Have you tried to google it?
    Doh, what am I doing, looking at the ISO working papers when cppreference.com is the real standard?

    Not to be mean, but that link really isn't even a good definition for "What is the STL".

    Anyhow, who decides what is/isn't part of the STL? Is SGI the de facto authority on this? It just seems to me there's bound to be some gray area in defining the boundaries.
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    C++ Witch laserlight's Avatar
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    Anyhow, who decides what is/isn't part of the STL? Is SGI the de facto authority on this? It just seems to me there's bound to be some gray area in defining the boundaries.
    The basis of the STL is a concept: separate generic algorithms and generic containers such that they can be mixed and matched. As a library, the STL is the original expression of that idea in C++, using C++ templates. So, it was Stepanov, Lee and their associates who decided what was part of the STL, and that is that. Under such a historical interpretation, std::string is not part of the STL.

    Of course, if we look at it as a term that is evolving in usage, then CornedBee's treatment of the term is probably best. After all, a new generic container added to the standard library could be seen (unofficially with respect to the standard) as being part of the STL portion of the standard library, even though its provenance is actually different.
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    Quote Originally Posted by QuestionC View Post
    That said, "Standard Template Library" is sort of an undefined term. I don't think it's actually part of the standard, and I've never heard it used in a manner distinguishable from "C++ Standard Library".
    Prior to 1998, there was no "C++ Standard Library", but there was the STL. In 1998 with the new standard, there became a C++ Standard Library which included the STL, but not ONLY the STL -- for example, the entirety of the C90 Standard Library, plus revisions of the pre-standard C++ libraries (iostream, etc) are all the Standard Library.

    When people speak of STL now, they're talking about the portion of the Standard Library which is derived from the STL, and not the portions which are from the C language, or the early C++ language. That is, the template-driven parts like vector<> and list<> and the like.

    STL is a subset of Standard Library.
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