//--------------------------------------------------------------------
// fileio2.cpp
//--------------------------------------------------------------------


// Reads a set of integer values from the file values.dat and outputs
// their sum to the file results.dat.

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

void main()
{
    ifstream inFile("values.dat");   // Open input file values.dat
    int num,                         // Number read from file
    sum = 0;                     // Sum of numbers read in

    // Check that input file opened correctly.
    if ( !inFile )
       cout << "values.dat could not be opened forinput" << endl;
    else
    {
       // Read in a set of numbers. Stop when the end of file is reached.
       while ( inFile.good()  &&  inFile >> num
)
           sum += num;

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

       // Open the output file results.dat.
       ofstream outFile("results.dat");

       // Check that output file opened correctly.
       if ( !outFile )
          cout << "sum.dat could not be opened for output" << endl;
       else
       {
          // Output the sum.
          outFile << "Sum = " << sum << endl;

          // Close the output file stream.
          outFile.close();
       }
    }
}