#include <iostream.h>
#include <limits.h>
#include <fstream.h>
#include "CPstring.h"

// file: stats4.cc; author: D. Ramm; date: 10/13/96
// file input; while with EOF to exit
// initialization from limits.h
// move stats to function with reference parameters

void Stats(int number, int & max, int & min, int & sum, int & count)
// Precondition: number is any integer data value, max, min,
//   sum, and count are previous best values for maximum, minimum
//   total sum, and count to numbers encountered.
// Postcondition:  max, min, sum, and count have been updated
//   appropriately.
{
   count++;
   sum += number;
   if (number > max)
   {
      max = number;
   }
   if (number < min)
   {
      min = number;
   }
}
   
int main()
{
   int number, count = 0;
   int sum = 0, max = INT_MIN, min = INT_MAX;
   string filename;
   ifstream filein;

   cout << "Enter file name: ";
   cin >> filename;

   filein.open(filename);

   while (filein >> number)
   {
      Stats(number, max, min, sum, count);
      cout << "Do something with number: " << number << endl;
   }
   if (count == 0)
      cout << "No data found in file " << filename << endl;
   else
      cout << "For " << count << " numbers read, Max = " << max
         << ", Min = " << min << ", Mean = " << 1.0*sum/count << endl;

   return 0;
}

Sample output:

stats4
Enter file name: data
Do something with number: 1
Do something with number: 2
Do something with number: 4
Do something with number: 7
Do something with number: -2
Do something with number: 33
Do something with number: -11
Do something with number: 12
For 8 numbers read, Max = 33, Min = -11, Mean = 5.75