#include <grass/gis.h>

void c_sum(DCELL *result, DCELL *values, int n)
{
	DCELL sum;
	int count;
	int i;

	sum = 0.0;
	count = 0;

	for (i = 0; i < n; i++)
	{
		if (G_is_d_null_value(&values[i]))
			continue;

		sum += values[i];
		count++;
	}

	if (count == 0)
		G_set_d_null_value(result, 1);
	else
		*result = sum;
}