while (! my_file.eof())

//-include the DebitCard implementation
#include "Card.h"
//-include the header for I/O
#include <iostream>
//-include header for files
#include <fstream>
#include <string>
//-using definitions
//-used as a shortcut
using std::cout;
using std::cin;
using std::endl;
 
/**main()
 *-definition of this file
 *-goes in the main method
 *-main method allows the
 *-program to be run
 **/
int main()
{
  DebitCard dc;
  //-char array for filename
  char filename[50];
  //-double for read amount
  double my_double = 0;
  //-char array to hold the information read
  char info[50];
  //-declaration of file object
  ifstream my_file;
 
  //-prompt the user
  cout << "Enter The File --> ";
  //-get the filename from the user
  cin.getline(filename, sizeof(filename));
  //-open the file based on the input
  my_file.open(filename);
 
  //-keep count of lines
  int count = 1;
  //-loop while it's no the end of the file
  while (! my_file.eof())
  {
    //-get the line from file
    my_file.getline(info,sizeof(info));
    //-store the value in a double
    //-this must be converted
    my_double = atof(info);
    //-if count is one, then we are on
    //-the first line and it is the balance
    //-to set the debit card to.
    if (count == 1)
    {
      //-print out the balance
      cout << "The Starting Balance Was --> " << my_double << endl;
      //-set the balance
      dc.set_balance(my_double);
    }
    else
    {
      //-variable for what should be withdrew
      double actual_amount = my_double;
      //-call the withdraw method
      dc.withdraw_from(my_double, actual_amount);
      //-if the actual amount withdrew is zero,
      //-then there was a problem
      if (actual_amount == 0)
      {
         //-show the user there was a problme
         cout << "Debit of $" << my_double << " -- Insufficent Funds" << endl;
      }
      else
      {
         //-show the user it was successfull.
         cout << "Debit of $" << my_double << " Completed" << endl;
      }
    }
  }
  //-close the file since we are done
  my_file.close();
 
  //-print the final balance of the card
  //-use the get_balance() method
  cout << "The Final Balance Is $" << dc.get_balance() << endl;
}

while (my_file.getline(info,sizeof(info)))

strtod ( s.c_str(), 0 );

#include <iostream>
#include <string>
#include <sstream>
 
template <typename T>
T jsw_strtot ( const std::string& s )
{
  std::istringstream iss ( s );
  T ret;
 
  iss>> ret;
 
  return ret;
}
 
int main()
{
  std::string s = "123.456";
  double d = jsw_strtot<double> ( s );
 
  std::cout<< d <<'\n';
}

#include <iostream>
#include <fstream>
#include <string>
 
int main()
{
  std::ifstream in ( "test" );
  std::string s;
 
  while ( !in.eof() ) {
    std::getline ( in, s );
    std::cout<< s <<'\n';
  }
}

This
is
a
test

#include <iostream>
#include <fstream>
#include <string>
 
int main()
{
  std::ifstream in ( "test" );
  std::string s;
 
  while ( std::getline ( in, s ) )
    std::cout<< s <<'\n';
}