Passing an array to a function in C++

passByPointer.cpp

#include <iostream>
using namespace std;

// Declare function: In this case, returns the average of the intigers contained in the array
double returnAverage(int arr[], int size)
{
	int i, sum = 0;
	double avg;

	for (i = 0; i < size; ++i)
	{
		sum += arr[i];
	}
	avg = double(sum) / size;

	return avg;
}

int main()
{
	// an int array with 5 elements.
	int intArray[5] = {1230, 14, 25, 17, 342};
	double avg;

	// Pass a pointer of the array to the function as an argument (this is the concept you are having trouble with).
	// (intArray, 5) is no different than (intArray[5]) In this case, it's always treated as a pointer.
	avg = returnAverage(intArray, 5);

	// Output the average value
	cout << "Average value is: " << avg << endl;

	return 0;
}

passByReference.cpp

// For Multi-Dimensional arrays, passing the array by reference without losing the dimension information is generally accepted
// assuming you know the dimensionality of the array at compile time.
template <size_t size_x, size_t size_y>
void func(double (&arr)[size_x][size_y])
{
	printf("%p\n", &arr);
}

int main()
{
	double a1[10][10];
	double a2[5][5];

	printf("%p\n%p\n\n", &a1, &a2);
	func(a1);
	func(a2);

	return 0;
}