Program to print Sum of even and odd elements in an array

Difficulty Level : Easy
Last Updated : 17 Mar, 2021

Prerequisite – Array Basics
Given an array, write a program to find the sum of values of even and odd index positions separately.
Examples:

Input : arr = {1, 2, 3, 4, 5, 6}
Output :Even index positions sum 9
        Odd index positions sum 12
Explanation: Here, n = 6 so there will be 3 even 
index positions and 3 odd index positions in an array
Even = 1 + 3 + 5 = 9
Odd =  2 + 4 + 6 = 12

Input : arr = {10, 20, 30, 40, 50, 60, 70}
Output : Even index positions sum 160
        Odd index positions sum 170
Explanation: Here, n = 7 so there will be 3 odd
index positions and 4 even index positions in an array
Even = 10 + 30 + 50 + 70 = 160
Odd = 20 + 40 + 60 = 120

C++

// CPP program to find out
// Sum of elements at even and
// odd index positions separately
#include <iostream>
   
using namespace std;
   
// Function to calculate sum
void EvenOddSum(int arr[], int n)
{
    int even = 0;
    int odd = 0;
    for (int i = 0; i < n; i++) {
        // Loop to find even, odd sum
        if (i % 2 == 0)
            even += arr[i];
        else
            odd += arr[i];
    }
   
    cout << "Even index positions sum " << even;
    cout << "\nOdd index positions sum " << odd;
}
   
// Driver function
int main()
{
    int arr[] = { 1, 2, 3, 4, 5, 6 };
    int n = sizeof(arr) / sizeof(arr[0]);
   
    EvenOddSum(arr, n);
   
    return 0;
}

Java

// Java program to find out
// Sum of elements at even and
// odd index positions separately
import java.io.*;
 
class EvenOddSum {
    public static void main(String args[])
    {
        int arr[] = { 1, 2, 3, 4, 5, 6 };
        int even = 0, odd = 0;
 
        // Loop to find even, odd sum
        for (int i = 0; i < arr.length; i++) {
            if (i % 2 == 0)
                even += arr[i];
            else
                odd += arr[i];
        }
 
        System.out.println("Even index positions sum: " + even);
        System.out.println("Odd index positions sum: " + odd);
    }
}

Python

# Python program to find out
# Sum of elements at even and
# odd index positions separately
 
# Function to calculate Sum
def EvenOddSum(a, n):
    even = 0
    odd = 0
    for i in range(n):
 
        # Loop to find evem, odd Sum
        if i % 2 == 0:
            even += a[i]
        else:
            odd += a[i]
     
    print "Even index positions sum ", even
    print "nOdd index positions sum ", odd
 
# Driver Function
 
arr = [1, 2, 3, 4, 5, 6]
n = len(arr)
 
EvenOddSum(arr, n)
 
# This code is contributed by Sachin Bisht

C#

// C# program to find out
// Sum of elements at even and
// odd index positions separately
using System;
 
public class GFG {
     
    public static void Main()
    {
        int[] arr = { 1, 2, 3, 4, 5, 6 };
        int even = 0, odd = 0;
 
        // Loop to find even, odd sum
        for (int i = 0; i < arr.Length; i++)
        {
            if (i % 2 == 0)
                even += arr[i];
            else
                odd += arr[i];
        }
 
        Console.WriteLine("Even index positions"
                             + " sum: " + even);
                              
        Console.WriteLine("Odd index positions "
                               + "sum: " + odd);
    }
}
 
// This code is contributed by Sam007.

PHP

<?php
// PHP program to find out
// Sum of elements at even and
// odd index positions separately
 
// Function to calculate sum
function EvenOddSum($arr, $n)
{
    $even = 0;
    $odd = 0;
    for ($i = 0; $i < $n; $i++)
    {
         
        // Loop to find even, odd sum
        if ($i % 2 == 0)
            $even += $arr[$i];
        else
            $odd += $arr[$i];
    }
 
    echo("Even index positions sum " . $even);
    echo("\nOdd index positions sum " . $odd);
}
 
// Driver Code
$arr = array( 1, 2, 3, 4, 5, 6 );
$n = sizeof($arr);
 
EvenOddSum($arr, $n);
 
// This code is contributed by Ajit.
?>

Javascript

<script>
 
// Javascript program to find out
// Sum of elements at even and
// odd index positions separately
 
// Function to calculate sum
function EvenOddSum(arr, n)
{
    let even = 0;
    let odd = 0;
    for (let i = 0; i < n; i++)
    {
     
        // Loop to find even, odd sum
        if (i % 2 == 0)
            even += arr[i];
        else
            odd += arr[i];
    }
 
    document.write("Even index positions sum " + even);
    document.write("<br>" + "Odd index positions sum " + odd);
}
 
// Driver function
    let arr = [ 1, 2, 3, 4, 5, 6 ];
    let n = arr.length;
 
    EvenOddSum(arr, n);
     
// This code is contributed by Mayank Tyagi
 
</script>

Output

Even index positions sum 9
Odd index positions sum 12

Method 2:Using slicing in python:

Calculate sum of all even indices using slicing and repeat the same with odd indices and print sum.

Below is the implementation:

Python3

# Python program to find out
# Sum of elements at even and
# odd index positions separately
 
# Function to calculate Sum
 
 
def EvenOddSum(a, n):
    even_sum = sum(a[::2])
    odd_sum = sum(a[1::2])
    print("Even index positions sum", even_sum)
    print("Odd index positions sum", odd_sum)
 
 
# Driver Function
 
arr = [1, 2, 3, 4, 5, 6]
n = len(arr)
 
EvenOddSum(arr, n)
 
# This code is contributed by vikkycirus

Output

Even index positions sum 9
Odd index positions sum 12

This article is contributed by Rishabh Jain. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
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