// ave1000.c: using arrays to compute an average of up to 1000 doubles
//          Reads integers until end-of-file with prompts for input.

#include <stdio.h>

const int MAX_ITEMS = 1000;

// compute average of an array, returning 0 if the array is empty
double ave(const double nums[], int size)
{
  double sum = 0.0;
  for(int i = 0; i < size; ++i)
    sum += nums[i];
  return size == 0 ? 0.0 : (sum / size);
}

int main()
{
  double nums[MAX_ITEMS];
  int count = 0;
  double next_number;
  printf("Enter a number: ");
  scanf("%lf", &next_number);
  while ( !feof(stdin) && count < MAX_ITEMS )
  {
    nums[count] = next_number;
    ++count;
    printf("Enter the next number: ");
    scanf("%lf", &next_number);
  }
  if ( count == 0 )
    printf("No average for an empty input.\n");
  else
    printf("Average: %.3g\n", ave(nums, count));
  return 0;
}