Cant use std namespace, help required

This is a discussion on Cant use std namespace, help required within the C++ Programming forums, part of the General Programming Boards category; I am unsure if this is a common problem, but i use VC++ 6.0, i am still learning, but i ...

  1. #1
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    Cant use std namespace, help required

    I am unsure if this is a common problem, but i use VC++ 6.0, i am still learning, but i cant seem to use anything from the std namespace.
    If i type std:: then the IDE gives me a list of everything in it, as though it is there, but when i try to compile it gives the error: std is not a namespace. Why is this? how do i use it?
    even in this simple (barely a) program it doesn't work:
    Code:
    int main(void)
    {
    	std::string mystring;
    	return 0;
    }
    thanks for helping,
    esaptonor

  2. #2
    Devil's Advocate SlyMaelstrom's Avatar
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    What libraries are you including? Are you including <iostream> or <iostream.h>, for example? The former uses the std namespace, the latter doesn't. There for, if you're including the latter libraries (with the .h extension) then you'll never have the std namespace defined in your code.
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  3. #3
    pwns nooblars
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    Get a compiler that conforms to standards... I do believe VC++ 6 you would just use string myString;

  4. #4
    C++ Witch laserlight's Avatar
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    even in this simple (barely a) program it doesn't work:
    It shouldnt work with any compiler in the world.

    I suggest you write:
    Code:
    #include <string>
    
    int main()
    {
    	std::string mystring;
    	return 0;
    }
    Get a compiler that conforms to standards... I do believe VC++ 6 you would just use string myString;
    Even MSVC6 is aware of namespaces.
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  5. #5
    pwns nooblars
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    Ah, kk, I know VC++ 6 does not conform to standards in a number of ways... just didn't feel like looking up the list.

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    Devil's Advocate SlyMaelstrom's Avatar
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    I don't think the issues with Visual C++ 6 goes beyond warning you when it shouldn't and not warning you when it should... I'm pretty sure as far as errors go, it's as spot on as any other modern compiler. I could be wrong on that, though.
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  7. #7
    The superhaterodyne twomers's Avatar
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    Have you tried -

    Code:
    #include <string>
    #include <iostream>
    
    using namespace std;
    
    int main( void )
    {
    	string mystring = "Namespace";
    	cout<< mystring;
    
    	return 0;
    }

  8. #8
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    thanks guys, i was using iostream.h, or nothing that defined it in, so once i included iostream or string it worked....i had only tried string.h, which doesn't work.

    thanks again,
    esaptonor

  9. #9
    The Richness... Richie T's Avatar
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    Read this about <iostream.h> vs <iostream>

    http://www.devx.com/tips/Tip/14447

    I don't think that iostream.h was part of the standard, it was only used during the drafting
    process. Nevertheless, it is a bad idea to use it since it is very outdated.
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  10. #10
    Useless Apprentice ryan_germain's Avatar
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    Quote Originally Posted by Richie T
    I don't think that iostream.h was part of the standard
    Anything with '.h' doesnt support namespaces. So when you add 'string.h' instead of just 'string', then std::string will not work.
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  11. #11
    Code Goddess Prelude's Avatar
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    >So when you add 'string.h' instead of just 'string', then std::string will not work.
    Correct, but not because of the std namespace. string.h is a C header with C string handling functions. It never has and likely never will host the string class.
    My best code is written with the delete key.

  12. #12
    Useless Apprentice ryan_germain's Avatar
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    >>Correct, but not because of the std namespace
    sorry my bad....was getting mixed up between the string and the cstring headers.

    so to undo what i did:

    include 'string' to add string class declared in std namespace
    now std::string will work

    include 'cstring' (which is the new 'string.h') for c-string functions declared in global namespace so no need for a using statement (or scope resolution) specifically for those functions
    There is not the slightest indication that [nuclear energy] will ever be obtainable. It would mean that the atom would have to be shattered at will.

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    >> include 'cstring' (which is the new 'string.h') for c-string functions declared in global namespace so no need for a using statement

    Actually the names inside the C++ versions of C library headers are all supposed to be in the std namespace as well. Some compilers still allow them to be accessed without the namespace, though.

    >> I'm pretty sure as far as errors go, it's as spot on as any other modern compiler.

    Not really. While it is fairly close in many regards, there is a significant amount of code that compiles on VC++ 6 that won't compile on modern compilers, and vice versa. The biggest issue is with templated code, but there are other differences as well.

  14. #14
    Useless Apprentice ryan_germain's Avatar
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    ok good to know...

    this runs on VC++6 so i imagine the cstring functions are in the global namespace for VC++6 though

    Code:
    #include <cstring>
    #include <iostream>
    
    int main(int argc, char* argv[])
    {
    	std::cout << strlen("hello");
    	return 0;
    }
    There is not the slightest indication that [nuclear energy] will ever be obtainable. It would mean that the atom would have to be shattered at will.

    -Albert Einstein, 1932

  15. #15
    Code Goddess Prelude's Avatar
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    >this runs on VC++6 so i imagine the cstring functions are in the global namespace for VC++6
    Of course, VC++6 is infamous for being horribly incompatible with standard C++.
    My best code is written with the delete key.

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