Program to find sum of elements in a given 2D array

Given a 2D array of order M * N, the task is to find out the sum of elements of the matrix.

Examples:

Input: array[2][2] = {{1, 2}, {3, 4}};
Output: 10

Input: array[4][4] = {{1, 2, 3, 4}, 
                                 {5, 6, 7, 8}, 
                                 {9, 10, 11, 12}, 
                                 {13, 14, 15, 16}};
Output: 136

Approach:

The sum of each element of the 2D array can be calculated by traversing through the matrix and adding up the elements.

Below is the implement the above approach-

C++

// C++ program to find sum of
// elements in 2D array
#include <iostream>
using namespace std;

// Get the size m and n
#define M 4
#define N 4

// Function to calculate sum
// of elements in 2d array
int sum(int arr[M][N])
{
    int i, j;
    int sum = 0;

    // Finding the sum
    for (i = 0; i < M; ++i) {
        for (j = 0; j < N; ++j) {
            // Add the element
            sum = sum + arr[i][j];
        }
    }
    return sum;
}

// Driver code
int main()
{
    int i, j;
    int arr[M][N];

    // Get the matrix elements
    int x = 1;
    for (i = 0; i < M; i++)
        for (j = 0; j < N; j++)
            arr[i][j] = x++;

    // Get sum
    cout << sum(arr);
    return 0;
}

Java

// Java code for the above approach
import java.io.*;

class GFG {
  // Get the size m and n
  static int M = 4;
  static int N = 4;

  // Function to calculate sum
  // of elements in 2d array
  static int sum(int arr[][])
  {
    int i, j;
    int sum = 0;

    // Finding the sum
    for (i = 0; i < M; ++i) {
      for (j = 0; j < N; ++j) {
        // Add the element
        sum = sum + arr[i][j];
      }
    }
    return sum;
  }

  public static void main (String[] args)
  {
    int i, j;
    int arr[][]= new int[M][N];

    // Get the matrix elements
    int x = 1;
    for (i = 0; i < M; i++)
      for (j = 0; j < N; j++)
        arr[i][j] = x++;

    // Get sum
    System.out.println(sum(arr));
  }
}

// This code is contributed by Potta Lokesh

Python3

# phython program to find sum of
# elements in 2D array

# Get the size m and n
M = 4
N = 4

# Function to calculate sum
# of elements in 2d array
def sum(arr):

    sum = 0

    # Finding the sum
    for i in range(M):
        for j in range(N):

            # Add the element
            sum = sum + arr[i][j]

    return sum

# Driver code
arr = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]

# Get the matrix elements
x = 1
for i in range(M):
    for j in range(N):
        arr[i][j] = x
        x += 1

# Get sum
print(sum(arr))

# This code is contributed by ninja_hattori

C#

using System;

class GFG
{

  // Get the size m and n
  static int M = 4;
  static int N = 4;

  // Function to calculate sum
  // of elements in 2d array
  static int sum(int [,]arr)
  {
    int i, j;
    int sum = 0;

    // Finding the sum
    for (i = 0; i < M; ++i)
    {
      for (j = 0; j < N; ++j)
      {

        // Add the element
        sum = sum + arr[i,j];
      }
    }
    return sum;
  }

  static public void Main (String[] args){
    int i, j;
    int [,]arr= new int[M,N];

    // Get the matrix elements
    int x = 1;
    for (i = 0; i < M; i++)
      for (j = 0; j < N; j++)
        arr[i,j] = x++;

    // Get sum
    Console.WriteLine(sum(arr));
    // Code
  }
}
// This code is contributed by Kritima Gupta

Javascript

    <script>
        // JavaScript program to find sum of
        // elements in 2D array

        // Get the size m and n
        const M = 4;
        const N = 4;

        // Function to calculate sum
        // of elements in 2d array
        const sum = (arr) => {
            let i, j;
            let sum = 0;

            // Finding the sum
            for (i = 0; i < M; ++i) {
                for (j = 0; j < N; ++j) {
                    // Add the element
                    sum = sum + arr[i][j];
                }
            }
            return sum;
        }

        // Driver code

        let i, j;
        let arr = new Array(M).fill(0).map(() => new Array(N).fill(0));

        // Get the matrix elements
        let x = 1;
        for (i = 0; i < M; i++)
            for (j = 0; j < N; j++)
                arr[i][j] = x++;

        // Get sum
        document.write(sum(arr));

// This code is contributed by rakeshsahni.
    </script>

Output

136

Time Complexity: O(M*N) 
Auxiliary Space: O(1)

Another Method: Using STL. Calling the inbuilt function for sum of elements of an array in STL. We use accumulate( first, last, sum) function to return the sum of 1D array.

Below is the implementation of idea.

C++

// C++ program to find sum of
// elements in 2D array
#include <iostream>
#include <numeric>
using namespace std;

// Get the size m and n
#define M 4
#define N 4

// Function to calculate sum
// of elements in 2d array
int sum(int arr[M][N])
{
    int i, j;
    int sum = 0;

    // Finding the sum
    for (i = 0; i < M; ++i) {
        int ans = 0;
        sum += accumulate(arr[i], arr[i] + N, ans);
    }
    return sum;
}

// Driver code
int main()
{
    int i, j;
    int arr[M][N];

    // Get the matrix elements
    int x = 1;
    for (i = 0; i < M; i++)
        for (j = 0; j < N; j++)
            arr[i][j] = x++;

    // Get sum
    cout << sum(arr);
    return 0;
}

Python

# phython program to find sum of
# elements in 2D array

# Get the size m and n
M = 4
N = 4

# Function to calculate sum
# of elements in 2d array


def Findsum(arr):

    ans = 0

    # Finding the sum
    for i in range(M):
        ans += int(sum(arr[i]))

    return ans


# Driver code
arr = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]

# Get the matrix elements
x = 1
for i in range(M):
    for j in range(N):
        arr[i][j] = x
        x += 1

# Get sum
print(Findsum(arr))

# This code is contributed by Sam_snehil

Javascript

// JavaScript program to find sum of
        // elements in 2D array

        // Get the size m and n
        const M = 4;
        const N = 4;

        // Function to calculate sum
        // of elements in 2d array
        const sum = (arr) => {
            let i, j;
            let sum = 0;

            // Finding the sum
            for (i = 0; i < M; ++i) {
                    sum = sum + arr[i].reduce(function(accumulator, currentValue){ return accumulator + currentValue;}, 0);

            }
            return sum;
        }

        // Driver code

        let i, j;
        let arr = new Array(M).fill(0).map(() => new Array(N).fill(0));

        // Get the matrix elements
        let x = 1;
        for (i = 0; i < M; i++)
            for (j = 0; j < N; j++)
                arr[i][j] = x++;

        // Get sum
        document.write(sum(arr));

// This code is contributed by rakeshsahni.

Output

136

Time Complexity: O(n*m) (where n = no. of rows and m = no. of column)

Auxiliary Space: O(1)