ambigious symbol error

This is a discussion on ambigious symbol error within the C++ Programming forums, part of the General Programming Boards category; If I have "using namespace std" in my code and try to use an ofstream object from the <fstream.h> header ...

  1. #1
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    ambigious symbol error

    If I have "using namespace std" in my code and try to use an ofstream object from the <fstream.h> header I get an Ambigious symbol error for ofstream.

    I need the namespace std for using strings from the <string> header.

    I fixed the problem by replacing "using namespace std" with "#define string std::string".

    It works fine for me, but other people will see this code, so what is the right way to fix this?

  2. #2
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    You need to use the new headers. fstream.h is deprecated. The new header is the same as old without the .h extension. So you need:

    #include <fstream>

    Most of the old headers such as math.h are now prefixed with a c and the .h removed. So the new math header is

    #include <cmath>
    "...the results are undefined, and we all know what "undefined" means: it means it works during development, it works during testing, and it blows up in your most important customers' faces." --Scott Meyers

  3. #3
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    standard header files no longer have the .h extension. try using just iostream without the .h if you use the line "using namespace std" in your code.

  4. #4
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    Using those headers gives me these errors on this line.

    Code:
    ofstream	outfile;
    error C2146: syntax error : missing ';' before identifier 'outfile'
    error C2501: 'ofstream' : missing storage-class or type specifiers
    error C2501: 'outfile' : missing storage-class or type specifiers

    Im at a loss...

  5. #5
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    What compiler are you using? Also are you still using using namespace std; ?
    Because...

    Code:
    #include <fstream>
    
    int main( void )
    {
      std::ofstream outfile;
    
      return 0;
    }
    Should compile no problem.
    "...the results are undefined, and we all know what "undefined" means: it means it works during development, it works during testing, and it blows up in your most important customers' faces." --Scott Meyers

  6. #6
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    Whoops, I was missing the namespace std in one of the headers.

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