/* hints2.c -- Read a sequence of positive integers and print them 
 *          out together with their sum. Use a Sentinel value
 *          (say 0) to determine when the sequence has terminated.
 *          You can compile the program with the command
 *             % cc hints2.c adder.c
 *          and run it with the command
 *             % a.out
 */

#include <stdio.h>
#include "adder.h"

#define SENTINEL 0

int main(void) {
  int current; /* The number just read */

  startup();                      /* Function defined in adder.c */
  do {
    printf("\nEnter an integer > ");
    scanf("%d", &current);
    if (current > SENTINEL)
      insert(current);            /* Function defined in adder.c */
  } while (current > SENTINEL);
  endup();                        /* Function defined in adder.c */
}
/*-----------------------------------------------------------------*/
/* adder.h -- Interface to adder module
 */

#ifndef ADDER_H_
#define ADDER_H_
  void startup(void);
  void insert(int current);
  void endup(void);
#endif
/*-----------------------------------------------------------------*/
/* adder.c -- The adder module
 */

#include <stdio.h>

static int count;  /* The number of numbers read. */
static int sum;    /* The sum of the numbers read */

void startup(void) {
  count = sum = 0;
}

void insert(int current) {
  count++;
  sum = sum + current;
}

void endup(void) {
  if (count)
    printf("The sum is %d and the average is %f\n", sum, (0.0+sum)/count);
  else
    printf("The sequence was empty\n");
}