// Oldham, Jeffrey D.
// 1999 Sep 07
// CS 1320
//
// Program to Add Many Integers

// input <- Prompted by the program, the user types zero or more integers.
// output-> The integers' sum is printed.

// We are now working on when to stop the while loop.  We want to stop 
// the while loop when there is no more input.  We want an expression
// that will yield true when an integer is typed and will yield false
// when no integer is typed.  The expression "cin >> second_integer"
// does just that!  The only problem is that it is in the middle of
// the loop body.

// Let's unroll the loop so we can use "cin >> second_integer" as the
// test.  The statements the loop performs look like:

//  cout << "Please enter an integer: ";    // first loop iteration
//  cin >> second_integer;
//  sum += second_integer;
//  cout << "Please enter an integer: ";    // second loop iteration
//  cin >> second_integer;
//  sum += second_integer;
//  ...					    // more loop iterations

// The loop below executes exactly the same statements.

// Try testing the program by typing inputs of zero integers, one
// integer, two integers, and three integers.

#include <iostream.h>

int main()
{
  int second_integer;
  int sum = 0;		// The sum of no integers is zero.

  cout << "Please enter an integer: ";
  while (cin >> second_integer)
  {
    sum += second_integer;	// Add the integer to the sum.
    cout << "Please enter an integer: ";
  }

  cout << "The sum is " << sum << ".\n";

  return 0;
}