// FILE: fig5.15.cc
// FINDS AND PRINTS THE SUM OF ALL INTEGERS FROM 1 TO n

#include <iostream.h>

int main () // standard C++
{
   // Local data ...
   int n;                      // last integer to be added to sum
   int sum;                    // sum of all integers from 1 to n
   int i;                      // loop control variable

   // Read the last integer.
   cout << "Enter the last integer in the sum: ";
   cin >> n;

   // Find the sum of all the integers from 1 to n inclusive.
   sum = 0;
   for (i = 1; i <= n; i++)
      sum += i;

   // Print the sum.
   cout << "The sum is " << sum << "." << endl;
   return 0; // no errors
}