/* Example: how to add the corresponding values from two arrays of the same size. */
#include <stdio.h>
 
/* Declare the function that adds the two arrays a1 and a2. It can compute
the array result[] because it gets address of the 0-th element result[0]
as one of its argument. Therefore, it can modify any elements in result[].
The type of this function is void because it returns all its work
implicitly by computing elements of result[].  The declaration "const"
indicates that the array must not be modified by the function.
*/
void addArrays (const int a1[], const int a2[], int result[], int n);

int main (void)
{
	int x[] = {1,2,3,4}, i;
	int y[] = {10,20,30,40};
	int z[4];

	/* Call the function with names of the arrays as factual arguments. 
	Recall that the name of an array is the address of the 0-th element
	in the array. In other words, we pass to this function addresses of 
	0-th elements of 3 arrays. Therefore, the function can modify any
	of the arguments unless an array is declared to be constant.  */

	addArrays (x, y, z, 4);

	/* print a report */
	for (i=0; i<4; ++i)
		printf ("%3d", x[i]);

	printf ("\n + \n");

	for (i=0; i<4; ++i)
		printf ("%3d", y[i]);

	printf ("\n-------------\n");

	for (i=0; i<4; ++i)
		printf ("%3d", z[i]);

	printf ("\n");

	return (0);
}


void addArrays (const int a1[], const int a2[], int result[], int n)
{
	int i;

	/* do the adding of every corresponding cells */
	for (i=0; i<n; ++i)
		result[i] = a1[i] + a2[i];
}