Question

If I change myfile(“input.txt”) to myfile(file_name)…where file_name is passed to the function it does not work but gives the error no matching function call..which I’m guessing b.c. I’m not suppose to be passing a string to the constructor…if not this way..how?

void file_to_string(string file_name)
{
   string line;  
   ifstream myfile("input.txt");
   if(myfile.is_open())
   {
      while(myfile.good())
      {
         getline(myfile,line);
         cout << line;
      }
      myfile.close();
  }
  else
  {
      cout << "File : " << file_name << " : did not open" ;
  }

}

int main(int argc, char *argv[])
{
    file_to_string(argv[1]);
}

Answer 1

Use the c_str() member of the std::string class:

ifstream myfile(file_name.c_str());

It returns a null-terminated const char * representation of the string in question, which is exactly what you need here.