/*          EECS 211
	Sample Program - Average
	
	Author:  	Larry Henschen
	Contact:	henschen@eecs.northwestern.edu
	Date:		January 9, 2008
		
	This program computes the average of a set of non-negative 
	integers.  It has many deficiencies and is meant only as
	a simple first illustration of a C++ program.

*/


#include <iostream>
using namespace std;

main()
{ 
	int number;			// The number of scores read.
  	int sum;				// The summation of all the scores read.
  	int grade;			// Holds each individual score as it is 
  									//    read from the keyboard.  
  									
  	float average;	// Holds the computed average.

    number = 0;			// Initialize number and sum to 0 before starting.
    sum = 0;

    cin >> grade;		// Get the first user input.

	// Loop as long as the input was non-negative.
    while(grade>=0) 
	{
        sum = sum + grade;		// Add new score into sum
        number = number + 1;	//   and count one more grade
        
		cin >> grade;					// Now get the next input.
    }

	// When done reading scores, compute average and display.
	average = (float)sum/number;
    cout << average;
    
    // When done, exit the program.
    return 0;

  }