c++

babag · 05-31-2008, 05:44 PM

i have this:

Code:

int main()
{
   ifstream infile("/home/user_acct/path/to/file/to/read.txt");

   if (!infile)
   {
      cerr << "Could not open file!"  <<  endl;

      return 1;
   }
}

i want to replace '/home/user_acct' with a variable so i can use
the code on more than one box but am getting errors. this is
something i've tried:

Code:

int main()
{
   char homepath = getenv("HOME");

   ifstream infile(homepath + "/path/to/file/to/read.txt");

   if (!infile)
   {
      cerr << "Could not open file!"  <<  endl;

      return 1;
   }
}

could someone show me how to do what i'm trying to do here?

thanks,
BabaG

AceofSpades19 · 05-31-2008, 05:57 PM

use strcat() or strncat() and use them to add the $HOME path on to the other path and then use ifstream to open the resulting variable

osor · 05-31-2008, 06:05 PM

A few things:

getenv returns a char * not a char.
Adding two char * variables does not concatenate them.
If you want to do the plain C way, you should have a buffer to hold the resulting filename and use strncat() on that.
Alternatively you can use realpath() with the ~ character as the home path.

If you want to go the C++ way, you can use std::string (which when added to a char* does what is expected). For example,

Code:

int main()
{
   std::string homepath = getenv("HOME");

   ifstream infile((homepath + "/path/to/file/to/read.txt").c_str());

   if (!infile)
   {
      cerr << "Could not open file!"  <<  endl;

      return 1;
   }
}

babag · 06-01-2008, 04:30 PM

perfect! thanks osor and AceOfSpades19.

BabaG