/*  Whilesum.c  (c) Kari Laitinen

    http://www.naturalprogramming.com

    2013-11-21  File created.
    2013-11-21  Last modification.

    Warning: The behaviour of this program can be
    strange if you type in letters when it is asking
    whole numbers. Typing Ctrl-C helps often when a
    program does not terminate correctly.
*/

#include  <stdio.h>

int main()
{
   int  integer_from_keyboard    =  -1 ;
   int  sum_of_integers          =   0 ;

   printf( "\n This program calculates the sum of integers you"
           "\n type in from the keyboard. By entering a zero you"
           "\n can terminate the program. \n\n" ) ;

   while ( integer_from_keyboard  !=  0 )
   {
      printf( "  Current sum: %8d    Enter an integer: ", sum_of_integers ) ;

      scanf( "%d", &integer_from_keyboard ) ;

      sum_of_integers  =  sum_of_integers + integer_from_keyboard ;
   }
}