How to add all elements of an array without using a C++ loop?

Question

C++ / C#

There is such a code, you need to add all the elements of an array without using a loop. Help me please.

#include <stdio.h>
#include <iostream>
#include <cstdlib>
#include <math.h>
using namespace std; 

int main() { 
int sum;
int students[3] = {
    1,
    4,
    7
};

sum = ?????????????;

printf("answer = %d", sum); 
return 0; 
}

Answer 1

#include <iostream>
#include <numeric>

int main (){
   const int arrayLength = 3; // раз уж вы пользуетесь массивом, то и длину точно знаете
   int students[arrayLength] = { 1, 4, 7 };   
   int sum = std::accumulate(students, students + arrayLength, 0);
   std::cout << "The array sum is " << sum << std::endl;
   return 0;
}

Answer 2

sum = students[0] + students[1] + students[2];

Answer 3

If the array is of reasonable size, you can enumerate everything by hand sum = students[0] + students[1] + students[2] + ... + students[n]