//--------------------------------------------------------------------
//
//  Example showing the use of the eof() function            eof.cpp
//
//--------------------------------------------------------------------

// Reads ALL the integer values from a user-specified input file and
// displays their sum.

#include <iostream.h>  // For cin and cout
#include <fstream.h>   // For file input/output

void main()
{
    ifstream inFile;    // Input file stream
    char filename[21];  // Input file name
    int num,            // Number read from file
        sum = 0;        // Sum of numbers read in

    // Get the file name.
    cout << "Enter file name (try values.dat): ";
    cin >> filename;

    // Open the input file.
    inFile.open( filename,ios::nocreate );

    // Check that input file opened correctly.
    if ( !inFile )
       cout << "File " << filename << " could not be opened for input"
            << endl;
    else
    {
       cout << endl;

       // Read in numbers, compute their sum, and output the result.
       while ( !inFile.eof() )   // <<<<<<< INCORRECT approach !!!!!!!
       {
           inFile >> num;
           cout << num << ' ';
           sum += num;
       }
       cout << endl << "Sum = " << sum << endl << endl;

       // Reset the file pointer to the start of the file.
       inFile.seekg(0);   // Reset pointer
       inFile.clear();    // Clear file flags (including eof)

       // Read in numbers, compute their sum, and output the result.
       sum = 0;
       while ( !inFile.eof() )   // <<<<<<< Awkward (correct) approach
       {
           inFile >> num;
           if ( !inFile.eof() )
           {
              cout << num << ' ';
              sum += num;
           }
       }
       cout << endl << "Sum = " << sum << endl << endl;

       // Reset the file pointer to the start of the file.
       inFile.seekg(0);   // Reset pointer
       inFile.clear();    // Clear file flags (including eof)

       // Read in numbers, compute their sum, and output the result.
       sum = 0;
       inFile >> num;
       while ( !inFile.eof() )   // <<<<<<< Better correct approach
       {
           cout << num << ' ';
           sum += num;
           inFile >> num;
       }
       cout << endl << "Sum = " << sum << endl << endl;

       // Reset the file pointer to the start of the file.
       inFile.seekg(0);   // Reset pointer
       inFile.clear();    // Clear file flags (including eof)

       // Read in numbers, compute their sum, and output the result.
       sum = 0;
       while ( inFile >> num )   // <<<<<<< Another correct approach
       {
           cout << num << ' ';
           sum += num;
       }
       cout << endl << "Sum = " << sum << endl << endl;

       // Close the input file stream.
       inFile.close();
    }
}