My first program and it doesn't work.

This is a discussion on My first program and it doesn't work. within the C++ Programming forums, part of the General Programming Boards category; PHP Code:      #include <iostream>      int main ()     {          std :: cout  <<  "Enter two numbers:"  <<  std :: endl ;          ...

  1. #1
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    My first program and it doesn't work.

    PHP Code:
        #include <iostream>
        
    int main()
        {
            
    std::cout << "Enter two numbers:" << std::endl;
            
    int v1v2;
            
    std::cin >> v1 >> v2;
            
    std::cout << "The sum of " << v1 << " and " << v2
                      
    << " is " << v1 v2 << std::endl;
            return 
    0;
        } 
    Could anyone tell me what's wrong with that? I've bought a book on C++ and all I get are compiler errors, such as;

    "'cout' is not a member of 'std'"
    "'endl' is not a member of 'std'"
    "'cin' is not a member of 'std'"
    "'cout' is not a member of 'std'"

    Obviously this is related to the 'std'. I've seen online tutorials not use the 'std' at all. Basically what I want to know is how I could fix that program, what 'std' is all about and finally why 'std' is used in some tutorials and not others.

    Any help will be much appreciated.

  2. #2
    Registered User mrafcho001's Avatar
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    what compiler?

    Try this
    Code:
    #include <iostream>
    using namespace std; 
    
    int main()
    {
       cout << "This should display." << endl; //no need for std::
    
    return 0;
    }

  3. #3
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    Wow, that was fast.

    I'm using Bloodshed Dev-C++, is that a problem? I've tried your version of the program and it gave me a whole new set of errors.

    See for yourself, screenshot: http://img149.imageshack.us/img149/8...eenshot1cy.jpg
    Last edited by Magneto; 07-16-2005 at 09:15 AM.

  4. #4
    Supermassive black hole cboard_member's Avatar
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    According to Bjarne Stroustrup, you should try this program to see if the compiler's conforming to the ISO standard. Dev-C++ does, so I have no idea why this doesn't work. Have you tried uninstalling it then reinstalling it - worth a try?

    http://www.research.att.com/~bs/compilers.html
    Good class architecture is not like a Swiss Army Knife; it should be more like a well balanced throwing knife.

    - Mike McShaffry

  5. #5
    Supermassive black hole cboard_member's Avatar
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    Ooo update: Are you using the Dev-C++ 5 beta? My friend who's also learning to program has informed me that it didn't work; he had similar problems. Get the next v down [v4.9.9.3 if I remember].
    Good class architecture is not like a Swiss Army Knife; it should be more like a well balanced throwing knife.

    - Mike McShaffry

  6. #6
    C++ Witch laserlight's Avatar
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    hmm... let's see, did you install the full package, or only the IDE?
    If you dont have a compiler set, you cant compile your programs.

    The version of Dev-C++ that you are using comes with an updated compiler (so the example should work), but if you choose to download and install the Dev-C++ IDE only, then there's no compiler to compile with.
    C + C++ Compiler: MinGW port of GCC
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    Well I only installed Dev-C++ today and I'm running 4.9.9.2 (It's been on my desktop a while). I could try reinstalling, but as I said I've only installed it today...

    Do you think I should try a different compiler?
    hmm... let's see, did you install the full package, or only the IDE?
    If you dont have a compiler set, you cant compile your programs.

    The version of Dev-C++ that you are using comes with an updated compiler (so the example should work), but if you choose to download and install the Dev-C++ IDE only, then there's no compiler to compile with.
    Full package.
    Last edited by Magneto; 07-16-2005 at 09:23 AM.

  8. #8
    C++ Witch laserlight's Avatar
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    Well I only installed Dev-C++ today and I'm running 4.9.9.2 (It's been on my desktop a while). I could try reinstalling, but as I said I've only installed it today...
    On the Dev-C++ download page, did you download "Dev-C++ 5.0 beta 9.2 (4.9.9.2) (9.0 MB) with Mingw/GCC 3.4.2" (devcpp-4.9.9.2_setup.exe) or "Dev-C++ 5.0 beta 9.2 (4.9.9.2), executable only (2.4 MB)" (devcpp-4.9.9.2_nomingw_setup.exe).

    If you downloaded the latter, you should download the former and do a re-install according to the uninstall/delete/reinstall procedure.
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  9. #9
    C++ Witch laserlight's Avatar
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    Full package.
    Okay, now go to the "Compile Log" tab and post your full compile log.
    C + C++ Compiler: MinGW port of GCC
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    I'm quite sure I downloaded ("Dev-C++ 5.0 beta 9.2 (4.9.9.2) (9.0 MB) with Mingw/GCC 3.4.2"). I'm going to unistall this version (whatever it is, I'm not sure) and install (devcpp-4.9.9.2_setup.exe). Just to eliminate that.

    This is what I get when I to compile this program:
    Code:
    #include <iostream>
        int main()
        {
            std::cout << "Enter two numbers:" << std::endl;
            int v1, v2;
            std::cin >> v1 >> v2;
            std::cout << "The sum of " << v1 << " and " << v2
                      << " is " << v1 + v2 << std::endl;
            return 0;
        }
    Compiler: Default compiler
    Executing g++.exe...
    g++.exe "C:\prog\ghfgjh.cpp" -o "C:\prog\ghfgjh.exe" -I"C:\Dev-Cpp\lib\gcc\mingw32\3.4.2\include" -I"C:\Dev-Cpp\include\c++\3.4.2\backward" -I"C:\Dev-Cpp\include\c++\3.4.2\mingw32" -I"C:\Dev-Cpp\include\c++\3.4.2" -I"C:\Dev-Cpp\include" -L"C:\Dev-Cpp\lib"
    C:\prog\ghfgjh.cpp:1:20: iostream: No such file or directory
    C:\prog\ghfgjh.cpp: In function `int main()':
    C:\prog\ghfgjh.cpp:4: error: `cout' is not a member of `std'
    C:\prog\ghfgjh.cpp:4: error: `endl' is not a member of `std'
    C:\prog\ghfgjh.cpp:6: error: `cin' is not a member of `std'
    C:\prog\ghfgjh.cpp:7: error: `cout' is not a member of `std'
    C:\prog\ghfgjh.cpp:8: error: `endl' is not a member of `std'

    Execution terminated
    If I try to compile this program:
    Code:
    #include <iostream>
    using namespace std; 
    
    int main()
    {
       cout << "This should display." << endl; //no need for std::
    
    return 0;
    }
    I get:
    Compiler: Default compiler
    Executing g++.exe...
    g++.exe "C:\prog\ghfgjh.cpp" -o "C:\prog\ghfgjh.exe" -I"C:\Dev-Cpp\lib\gcc\mingw32\3.4.2\include" -I"C:\Dev-Cpp\include\c++\3.4.2\backward" -I"C:\Dev-Cpp\include\c++\3.4.2\mingw32" -I"C:\Dev-Cpp\include\c++\3.4.2" -I"C:\Dev-Cpp\include" -L"C:\Dev-Cpp\lib"
    C:\prog\ghfgjh.cpp:1:20: iostream: No such file or directory
    C:\prog\ghfgjh.cpp: In function `int main()':
    C:\prog\ghfgjh.cpp:6: error: `cout' undeclared (first use this function)
    C:\prog\ghfgjh.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
    C:\prog\ghfgjh.cpp:6: error: `endl' undeclared (first use this function)

    Execution terminated

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    It must have been something to do with my compiler. I've reinstalled Dev-C++ using that guide you gave me. The version I have installed now is, Dev-C++ 5.0 beta 9.2 (4.9.9.2) (9.0 MB) with Mingw/GCC 3.4.2.

    Both programs worked. Thanks a lot everyone!

    I'm curious though, what is 'std::'? What's It's purpose? Why is it used if it's not needed?

  12. #12
    Supermassive black hole cboard_member's Avatar
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    It's a namespace. Think of it as a wrapper around some classes & functions to ensure no conflicts occur. This menas you could write a function named cout, and place it in a different namespace (or leave it in the global namespace) without fear of it being mis-interpreted by your compiler. I strongly reccommend you don't do that.
    Good class architecture is not like a Swiss Army Knife; it should be more like a well balanced throwing knife.

    - Mike McShaffry

  13. #13
    Registered User mrafcho001's Avatar
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    Quote Originally Posted by Magneto
    It must have been something to do with my compiler. I've reinstalled Dev-C++ using that guide you gave me. The version I have installed now is, Dev-C++ 5.0 beta 9.2 (4.9.9.2) (9.0 MB) with Mingw/GCC 3.4.2.

    Both programs worked. Thanks a lot everyone!

    I'm curious though, what is 'std::'? What's It's purpose? Why is it used if it's not needed?
    Don't worry about it.. when you get to namespaces youll see why its there

  14. #14
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    Just so you know this was your error
    C:\prog\ghfgjh.cpp:1:20: iostream: No such file or directory
    So apparantly the packages you got didnt install correctly for some reason.

  15. #15
    Registered User mrafcho001's Avatar
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    Quote Originally Posted by JoshR
    Just so you know this was your error

    So apparantly the packages you got didnt install correctly for some reason.
    Im pretty sure when i had Dev-C++ when i installed it there was something about installing the libraries. Maybe he checked that off or something.

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