Calculate Sum of the Elements of the Array

Problem Statement: Given an array, we have to find the sum of all the elements in the array.

Examples:

Example 1:
Input: N = 5, array[] = {1,2,3,4,5}
Output: 15
Explanation: Sum of all the elements is 1+2+3+4+5 = 15

Example 2:
Input:  N=6, array[] = {1,2,1,1,5,1}
Output: 11
Explanation: Sum of all the elements is 1+2+1+1+5+1 = 11

Disclaimer: Don’t jump directly to the solution, try it out yourself first.

Solution 1: Using for loop                                                                                                                                             

Approach

  • Using for loop traverse through the array and while traversing  maintain  a variable for storing sum of the elements in the array.
  • After completing the traversal simply print the sum.

Code:

C++ Code

#include<bits/stdc++.h>
using namespace std;
int main() {
	int n = 5;
	vector<int>arr = {1, 2, 3, 4, 5};
	int sum = 0;
	for (int i = 0; i < n; i++) {
		sum += (double)arr[i];
	}
	cout <<"The sum of the elements of the array is "<< sum;
}

Output:

The sum of the elements of the array is 15

Time Complexity: O(n) As we traverse the array once.

Space Complexity: O(1).

Java Code

import java.util.*;
public class Main {
  public static void main(String args[]) {
    int n = 5;
    int arr[] = {1,2,3,4,5};
    int sum = 0;
    for (int i = 0; i < n; i++) {
      sum += arr[i];
    }
    System.out.println("The sum of the elements of the array is "+sum);
  }
}

Output:

The sum of the elements of the array is 15

Time Complexity: O(n) As we traverse the array once.

Space Complexity: O(1).

Solution 2: Using collection in Java or STL in C++

Approach:

For C++: “accumulate” is used to calculate the sum of all the elements in the array.    

For Java: Instream sum() gives the sum of all the elements in the stream.

Code:

C++ Code

#include<bits/stdc++.h>
using namespace std;
int main() {

	int n = 5;
	int arr[] = {1, 2, 3, 4, 5};
	int initialSum = 0;
	cout <<"The sum of the elements of the array is ";
	cout<<accumulate(arr, arr + n, initialSum);

}

Output:

The sum of the elements of the array is 15

Time Complexity: O(n).

Space Complexity: O(1).

Java Code

import java.util.*;
import java.util.stream.IntStream;
public class Main {
  public static void main(String args[]) {
    int n = 5;
    int arr[] = {1,2,3,4,5};
    int sum = IntStream.of(arr).sum();
    System.out.println("The sum of the elements of the array is "+sum);
  }
}

Output:

The sum of the elements of the array is 15

Time Complexity: O(n).

Space Complexity: O(1).

Special thanks to Pranav Padawe for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article