Variable file names in file i/o

This is a discussion on Variable file names in file i/o within the C++ Programming forums, part of the General Programming Boards category; Hello. I'm trying to write a program that includes saving text to a file. I wish to have the filename ...

  1. #1
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    Variable file names in file i/o

    Hello. I'm trying to write a program that includes saving text to a file. I wish to have the filename entered by the user. I know how to write to a file, but I'm not sure how to allow the user to define that file. This is the function I tried creating, and when added, my program will not compile:
    Code:
    void filewrite() {
    string filen = "";
    cout<<"Enter filename(will be overwitten if exists):";
    cin>>filen;
     ofstream myfile;
      myfile.open (filen, ios::trunc);
      myfile << "Writing this to a file.\n";
      myfile.close();
    }
    I appreciate any assistance you can render me.

    Edit:
    Here are my includes:
    Code:
    #include <iostream>
    #include <sstream>
    #include <fstream>
    Here is the error:

    cpp:15: error: no matching function for call to ‘std::basic_ofstream<char, std::char_traits<char> >:pen(std::string&, const std::_Ios_Openmode&)’
    /usr/include/c++/4.3/fstream:626: note: candidates are: void std::basic_ofstream<_CharT, _Traits>:pen(const char*, std::_Ios_Openmode) [with _CharT = char, _Traits = std::char_traits<char>]
    Last edited by jesseee; 01-14-2009 at 10:52 PM. Reason: Adding more info

  2. #2
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    > myfile.open (filen, ios::trunc);
    Use
    myfile.open (filen.c_str(), ios::trunc);

    The clue in the error message is here
    candidates are: void std::basic_ofstream<_CharT, _Traits>::open(const char*, std::_Ios_Openmode) [with _CharT = char, _Traits = std::char_traits<char>]

    The c_str() method of a string returns something of the appropriate type.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  3. #3
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    Thank you very much. I suspect this method will come in very handy in the future.

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