String to char

What am i missing here? How do I reinterpret the string to char for use with the fileobject.open? I'll slap out quick source for visual. ::baffled::

Code:

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#include <string>
#include <iostream>
#include <fstream>

void LoadFile(string filename)
{
    ifstream fileobject;
    fileobject.open(filename, ios::binary);
}

int main(int argc, char *argv[])
{
      string filename;
      filename = "test.txt";
      LoadFile(filename);
      return 1;
}

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Use the c_str method.

Code:

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filename.c_str()

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Damn. Should of realised that. Thanks.