Calculate the Sum of Elements in an Array (C++)

Understanding Sum Calculation

Summing elements in an array involves adding all the elements together to get a total sum.

We will explore three different methods to calculate the sum of an array using C++.

Method 1: Using a Loop

This method iterates through the array and accumulates the sum.

#include <iostream>
using namespace std;

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    int sum = 0;
    
    for(int i = 0; i < n; i++) {
        sum += arr[i];
    }
    
    cout << "Sum: " << sum;
    return 0;
}

Output: Sum: 15

Method 2: Using Recursion

This method calculates the sum recursively.

#include <iostream>
using namespace std;

int sum_recursive(int arr[], int n) {
    if (n == 0) return 0;
    return arr[n - 1] + sum_recursive(arr, n - 1);
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    cout << "Sum: " << sum_recursive(arr, n);
    return 0;
}

Output: Sum: 15

Method 3: Using Array Traversal with Pointers

This method calculates the sum using pointers.

#include <iostream>
using namespace std;

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    int sum = 0, *ptr;
    
    for(ptr = arr; ptr < arr + n; ptr++) {
        sum += *ptr;
    }
    
    cout << "Sum: " << sum;
    return 0;
}

Output: Sum: 15