What does this program do? Can someone kindly shed some light on this for me please.

[jessiej6]

#include <iostream>

#include <array>

using namespace std;




const size_t arraySize{10};

int whatIsThis(const array<int, arraySize>&, size_t); // prototype




int main() {

array<int, arraySize> a{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};




int result{whatIsThis(a, arraySize)};




cout << "Result is " << result << endl;

}




// What does this function do?

int whatIsThis(const array<int, arraySize>& b, size_t size) {

if (size == 1) { // base case

return b[0];

}

else { // recursive step

return b[size - 1] + whatIsThis(b, size - 1);

}

}