Sum of even numbers at even position

13 Jun, 2022
Given an array of size n. The problem is to find the sum of numbers which are even and are at even index.Examples:  
Input :  arr[] = {5, 6, 12, 1, 18, 8}
Output : 30
Explanation: Here, n = 6 
Now here are index and numbers as: index->arr[index]
0->5, 1->6, 2->12, 3->1, 4->18, 5->8
so, number which are even and are at even indices 
are: 2->12, 4->18
sum = 12+18 = 30

Input  : arr[] = {3, 20, 17, 9, 2, 10, 
                        18, 13, 6, 18}
Output : 26
Explanation: Here, n = 10
Now here are index and numbers as: index->arr[index]
0->3, 1->20, 2->17, 3->9, 4->2, 5->10, 
6->18, 7->13, 8->6, 9->18 
So, number which are even and are at even indices are: 
4->2, 6->18, 8->6
sum = 2+18+6 = 26
 
 
C++
Java
Python3
C#
PHP
Javascript
// C++ implementation to// find sum of even numbers// at even indices#include <bits/stdc++.h>using namespace std; // Function to calculate sum// of even numbers at even indicesint sum_even_and_even_index(                int arr[], int n) {     int i = 0, sum = 0;         // calculating sum of even    // number at even index    for (i = 0; i < n; i+=2) {             if (arr[i] % 2 == 0) {                         sum += arr[i];        }    }         // required sum    return sum;} // Driver program to test aboveint main() {    int arr[] = {5, 6, 12, 1, 18, 8};    int n = sizeof(arr) / sizeof(arr[0]);    cout << "Sum of even numbers at even indices is "         << sum_even_and_even_index(arr, n);         return 0;}
// Java implementation to find sum of// even numbers at even indices import java.io.*; class GFG {         // Function to calculate sum    // of even numbers at even indices    static int sum_even_and_even_index(                       int arr[], int n)    {             int i = 0, sum = 0;                 // calculating sum of even        // number at even index        for (i = 0; i < n; i+=2) {                     if (arr[i] % 2 == 0) {                sum += arr[i];            }        }                 // required sum        return sum;    }     // Driver program to test above    public static void main (String[] args) {                 int arr[] = {5, 6, 12, 1, 18, 8};        int n = arr.length;        System.out.println("Sum of even numbers"                      + " at even indices is " +             + sum_even_and_even_index(arr, n));    }} // This code is contributed by vt_m.
# python 3 implementation to# find sum of even numbers# at even indices # Function to calculate sum# of even numbers at even indicesdef sum_even_and_even_index(arr,n):         i = 0    sum = 0     # calculating sum of even# number at even index    for i in range(0,n,2):        if (arr[i] % 2 == 0) :            sum += arr[i]             # required sum    return sum  # Driver program to test abovearr = [5, 6, 12, 1, 18, 8]n = len(arr)print("Sum of even numbers at ",             "even indices is ",   sum_even_and_even_index(arr, n))     # This code is contributed by Sam007
// C# implementation to find sum of// even numbers at even indices using System; class GFG {         // Function to calculate sum    // of even numbers at even indices    static int sum_even_and_even_index(                    int []arr, int n)    {             int i = 0, sum = 0;                 // calculating sum of even        // number at even index        for (i = 0; i < n; i+=2) {                     if (arr[i] % 2 == 0) {                                 sum += arr[i];            }        }                 // required sum        return sum;    }     // Driver program to test above    public static void Main () {                 int []arr = {5, 6, 12, 1, 18, 8};        int n = arr.Length;        Console.WriteLine("Sum of even numbers"                    + " at even indices is " +            + sum_even_and_even_index(arr, n));    }} //This code is contributed by vt_m.
<?php// PHP implementation to// find sum of even numbers// at even indices // Function to calculate sum// of even numbers at even indicesfunction sum_even_and_even_index($arr, $n){     $i = 0; $sum = 0;         // calculating sum of even    // number at even index    for ($i = 0; $i < $n; $i=$i+2) {             if ($arr[$i] % 2 == 0) {                         $sum += $arr[$i];        }    }         // required sum    return $sum;} // Driver Code{    $arr = array(5, 6, 12, 1, 18, 8);    $n = sizeof($arr) / sizeof($arr[0]);    echo "Sum of even numbers at ".                 "even indices is ",          sum_even_and_even_index($arr, $n);         return 0;} // This code is contributed by nitin mittal.?>
<script> // Javascript implementation to// find sum of even numbers// at even indices // Function to calculate sum// of even numbers at even indicesfunction sum_even_and_even_index(                arr, n) {     let i = 0, sum = 0;         // calculating sum of even    // number at even index    for (i = 0; i < n; i += 2)    {        if (arr[i] % 2 == 0)        {               sum += arr[i];        }    }         // required sum    return sum;} // Driver code    let arr = [5, 6, 12, 1, 18, 8];    let n = arr.length;    document.write("Sum of even numbers at even indices is "        + sum_even_and_even_index(arr, n));     // This code is contributed by Mayank Tyagi </script>
Output:  
 Sum of even numbers at even indices is 30
Time Complexity: O(n)
Auxiliary Space: O(1) 
nitin mittal
Sam007
shashank2714
mayanktyagi1709
hasani
Arrays
School Programming
Arrays
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Maximum and minimum of an array using minimum number of comparisons
Top 50 Array Coding Problems for Interviews
Multidimensional Arrays in Java
Stack Data Structure (Introduction and Program)
Linear Search
Python Dictionary
Reverse a string in Java
Introduction To PYTHON
Interfaces in Java
Inheritance in C++