5.6 C++ How to Program (8th Edition) By Paul Deitel, Harvey Deitel

(Averaging Integers) Write a program that uses a for statement to calculate the average of several integers. Assume the last value read is the sentinel 9999.

For example, the sequence 10 8 11 7 9 9999 indicates that the program should calculate the average of all the values preceding 9999.

Solution:

#include < iostream>
 
using namespace std;
 
int main()
{
  int sum;
  int counter = 0;
 
  cout << "Enter integers for average calculation."
      << "Enter 9999 to end." << endl;
  cin >> sum;
 
   for( int x = 0; x != 9999; counter++){
      sum += x;
      cin >> x;
   }   
 
   cout << "Average is " << sum/counter << endl;
 
   //for pause
   system("PAUSE");
   return 0;
}