C++ Array Sum Algorithm

4 min read Jul 05, 2024

C++ Array Sum Algorithm

This article will explain how to calculate the sum of all elements in a C++ array using different algorithms.

1. Simple Iteration Algorithm

This is the most straightforward and widely used method. We iterate through each element of the array, adding it to a running sum variable.

#include 

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];
  }

  std::cout << "Sum of array elements: " << sum << std::endl;
  return 0;
}

In this code:

arr is our array containing the elements.
n calculates the number of elements in the array.
sum is initialized to 0 to store the running sum.
The for loop iterates through the array, adding each element to sum.
Finally, the calculated sum is printed.

2. Using `std::accumulate`

The C++ Standard Template Library (STL) provides a powerful function, std::accumulate, specifically designed for calculating sums.

#include 
#include 

int main() {
  int arr[] = {1, 2, 3, 4, 5};
  int sum = std::accumulate(std::begin(arr), std::end(arr), 0);

  std::cout << "Sum of array elements: " << sum << std::endl;
  return 0;
}

Here:

We include the <numeric> header for the std::accumulate function.
std::begin(arr) and std::end(arr) return iterators to the beginning and end of the array, respectively.
0 is the initial value of the sum.

3. Recursive Approach

We can calculate the sum recursively by breaking the problem into smaller subproblems.

#include 

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

int main() {
  int arr[] = {1, 2, 3, 4, 5};
  int n = sizeof(arr) / sizeof(arr[0]);
  int sum = sum_array(arr, n);

  std::cout << "Sum of array elements: " << sum << std::endl;
  return 0;
}

In this code:

sum_array is a recursive function that takes the array and its size as arguments.
The base case is when the array size n is 0, returning 0.
Otherwise, it returns the sum of the last element arr[n-1] and the recursive call to sum_array with the rest of the array.

Conclusion

This article provides different approaches to calculating the sum of elements in a C++ array. Choose the method that best suits your needs and coding style. The STL's std::accumulate is a convenient option, but understanding the iterative and recursive methods is valuable for improving your understanding of algorithms and programming fundamentals.

C++ Array Sum Algorithm