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++
// 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 indices 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 int 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; } |
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Java
// 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. |
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Python3
# python 3 implementation to # find sum of even numbers # at even indices # Function to calculate sum # of even numbers at even indices def 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 above arr = [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 |
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C#
// 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. |
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PHP
<?php // PHP implementation to // find sum of even numbers // at even indices // Function to calculate sum // of even numbers at even indices function 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. ?> |
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Output:
Sum of even numbers at even indices is 30
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