File handling; C way cont.

 out_file = fopen( argv[2], "w"); // returns a pointer to the output file
 if( out_file == NULL )  {       // can't find the file
    printf("Can't find the output file%s\n", argv[2]);
    exit(0);
  }
  fclose(in_file);
  fclose(out_file);
  return 0;