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

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 120
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 ```
Recommended Practice

Implementation:

## C++

 `// CPP program to find out ` `// Sum of elements at even and ` `// odd index positions separately ` `#include ` `  `  `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);` `    ``}` `}`

## 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 ``=` `0` `    ``odd ``=` `0` `    ``for` `i ``in` `range``(n):`   `        ``# Loop to find even, 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

 ``

## Javascript

 ``

Output

```Even index positions sum 9
Odd index positions sum 12```

Time Complexity: O(length(arr))
Auxiliary Space: 0(1)

## C++

 `// CPP program to find out ` `// Sum of elements at even and ` `// odd index positions separately  using bitwise & operator` `#include ` `  `  `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 & 1 != 0) ` `            ``odd += arr[i]; ` `        ``else` `            ``even += 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; ` `} `   `//This code is contributed by Vinay Pinjala.`

## Java

 `// Java program to find out` `// Sum of elements at even and` `// odd index positions separately using bitwise & operator` `public` `class` `Main {` `  ``public` `static` `void` `main(String[] args)` `  ``{` `    ``int``[] arr = { ``1``, ``2``, ``3``, ``4``, ``5``, ``6` `};` `    ``int` `n = arr.length;` `    ``int` `even = ``0``;` `    ``int` `odd = ``0``;` `    ``for` `(``int` `i = ``0``; i < n; i++)` `    ``{`   `      ``// Loop to find even, odd sum` `      ``if` `((i & ``1``) != ``0``) {` `        ``odd += arr[i];` `      ``}` `      ``else` `{` `        ``even += arr[i];` `      ``}` `    ``}` `    ``System.out.println(``"Even index positions sum: "` `                       ``+ even);` `    ``System.out.println(``"Odd index positions sum: "` `                       ``+ odd);` `  ``}` `}`   `// This code is contributed by divyansh2212`

## Python3

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

## C#

 `using` `System;`   `namespace` `TestApplication` `{` `  ``class` `Program` `  ``{` `    ``static` `void` `Main(``string``[] args)` `    ``{` `      ``int``[] arr = { 1, 2, 3, 4, 5, 6 };` `      ``int` `n = arr.Length; ` `      ``int` `even = 0;` `      ``int` `odd = 0;` `      ``for` `(``int` `i = 0; i < n; i++)` `      ``{` `        ``// Loop to find even, odd sum` `        ``if` `((i & 1) != 0)` `        ``{` `          ``odd += arr[i];` `        ``}` `        ``else` `        ``{` `          ``even += arr[i];` `        ``}` `      ``}` `      ``Console.WriteLine(``"Even index positions sum: "` `+ even);` `      ``Console.WriteLine(``"Odd index positions sum: "` `+ odd);` `    ``}` `  ``}` `}`

## Javascript

 `// JS program to find out ` `// Sum of elements at even and ` `// odd index positions separately  using bitwise & operator`   `// 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 & 1 != 0) ` `            ``odd += arr[i]; ` `        ``else` `            ``even += arr[i]; ` `    ``} ` `  `  `    ``console.log(``"Even index positions sum "` `+ even); ` `    ``console.log(``"\nOdd index positions sum "` `+ odd); ` `} ` `  `  `// Driver function ` `let arr = [ 1, 2, 3, 4, 5, 6 ]; ` `let n = arr.length; `   `EvenOddSum(arr, n); ` ` `

Output

```Even index positions sum 9
Odd index positions sum 12```

Time Complexity: O(length(arr))
Auxiliary Space: 0(1)

#### Method 3: 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:

## C++

 `#include ` `using` `namespace` `std;`   `// Function to calculate sum` `int` `EvenOddSum(``int` `arr[] , ``int` `n)` `{` `  ``int` `even = 0;` `  ``int` `odd = 0;`   `  ``// Loop to find even, odd sum` `  ``for` `(``int` `i = 0; i < n; i++) {` `    ``if` `(i % 2 == 0)` `      ``even += arr[i];` `    ``else` `      ``odd += arr[i];` `  ``}` `  ``cout<<``"Even index positions sum "``<

## Java

 `// Java program to find out sum of elements at even` `// and odd index positions separately`   `import` `java.io.*;`   `class` `GFG {`   `    ``// Function to calculate sum` `    ``static` `void` `EvenOddSum(``int``[] arr, ``int` `n)` `    ``{` `        ``int` `even = ``0``;` `        ``int` `odd = ``0``;`   `        ``// Loop to find even, odd sum` `        ``for` `(``int` `i = ``0``; i < n; i++) {` `            ``if` `(i % ``2` `== ``0``)` `                ``even += arr[i];` `            ``else` `                ``odd += arr[i];` `        ``}` `        ``System.out.println(``"Even index positions sum "` `                           ``+ even);` `        ``System.out.print(``"Odd index positions sum "` `+ odd);` `    ``}`   `    ``public` `static` `void` `main(String[] args)` `    ``{` `        ``int``[] arr = { ``1``, ``2``, ``3``, ``4``, ``5``, ``6` `};` `        ``int` `n = arr.length;`   `        ``EvenOddSum(arr, n);` `    ``}` `}`   `// This code is contributed by lokeshmvs21.`

## 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`

## C#

 `// C# program to find out sum of elements at even` `// and odd index positions separately` `using` `System;`   `public` `class` `GFG {`   `    ``// Function to calculate sum` `    ``static` `void` `EvenOddSum(``int``[] arr, ``int` `n)` `    ``{` `        ``int` `even = 0;` `        ``int` `odd = 0;`   `        ``// Loop to find even, odd sum` `        ``for` `(``int` `i = 0; i < n; 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);` `    ``}`   `    ``static` `public` `void` `Main()` `    ``{`   `        ``// Code` `        ``int``[] arr = { 1, 2, 3, 4, 5, 6 };` `        ``int` `n = arr.Length;`   `        ``EvenOddSum(arr, n);` `    ``}` `}`   `// This code is contributed by lokeshmvs21.`

## Javascript

 ``

Output

```Even index positions sum 9
Odd index positions sum 12```

Time Complexity: O(n) where n is no of elements in given array
Auxiliary Space: 0(1)

Method 2: Using bitwise | operator

## C++14

 `// C++ program to find out` `// Sum of elements at even and ` `// odd index positions separately using bitwise | operator`   `#include` `using` `namespace` `std;` `// Function to calculate Sum` `void` `EvenOddSum(vector<``int``>a, ``int` `n)` `{` `    ``int` `even = 0;` `    ``int` `odd = 0;` `    ``for``(``int` `i=0; iarr = {1, 2, 3, 4, 5, 6};` `    ``int` `n = arr.size();` `    `  `    ``EvenOddSum(arr, n);` `}`

## Python3

 `# Python program to find out` `# Sum of elements at even and ` `# odd index positions separately using bitwise | operator`   `# Function to calculate Sum` `def` `EvenOddSum(a, n):` `    ``even ``=` `0` `    ``odd ``=` `0` `    ``for` `i ``in` `range``(n):`   `        ``# Loop to find even, odd Sum` `        ``if` `i|``1``=``=``i:` `          ``odd``+``=``a[i]` `        ``else``:` `          ``even``+``=``a[i]` `    ``print` `(``"Even index positions sum "``, even)` `    ``print` `(``"Odd index positions sum "``, odd)`   `# Driver Function`   `arr ``=` `[``1``, ``2``, ``3``, ``4``, ``5``, ``6``]` `n ``=` `len``(arr)`   `EvenOddSum(arr, n)`

## Javascript

 `// JavaScript program to find out` `// Sum of elements at even and ` `// odd index positions separately using bitwise | operator`   `// Function to calculate Sum` `function` `EvenOddSum(a, n) {` `  ``let even = 0;` `  ``let odd = 0;` `  ``for``(let i = 0; i < n; i++) {` `    ``// Loop to find even, odd Sum` `    ``if` `((i|1) === i)` `      ``odd += a[i];` `    ``else` `      ``even += a[i];` `  ``}` `  ``console.log(``"Even index positions sum "``, even);` `  ``console.log(``"Odd index positions sum "``, odd);` `}`   `// Driver Function`   `  ``const arr = [1, 2, 3, 4, 5, 6];` `  ``const n = arr.length;`   `  ``EvenOddSum(arr, n);`

## Java

 `import` `java.util.*;`   `class` `Main {` `    ``// Function to calculate Sum of elements at even and odd` `    ``// index positions separately` `    ``static` `void` `EvenOddSum(List a, ``int` `n)` `    ``{` `        ``int` `even = ``0``;` `        ``int` `odd = ``0``;` `        ``for` `(``int` `i = ``0``; i < n; i++) {` `            ``// Loop to find even, odd Sum` `            ``if` `((i | ``1``) == i) {` `                ``odd += a.get(i);` `            ``}` `            ``else` `{` `                ``even += a.get(i);` `            ``}` `        ``}` `        ``// Print the sum of elements at even and odd index` `        ``// positions` `        ``System.out.println(``"Even index positions sum "` `                           ``+ even);` `        ``System.out.println(``"Odd index positions sum "` `                           ``+ odd);` `    ``}`   `    ``// Driver Function` `    ``public` `static` `void` `main(String[] args)` `    ``{` `        ``// Create a list of integers` `        ``List arr = ``new` `ArrayList<>(` `            ``Arrays.asList(``1``, ``2``, ``3``, ``4``, ``5``, ``6``));` `        ``// Get the size of the list` `        ``int` `n = arr.size();` `        ``// Call the EvenOddSum function` `        ``EvenOddSum(arr, n);` `    ``}` `}`

## C#

 `// C# program to find out` `// Sum of elements at even and` `// odd index positions separately using bitwise | operator`   `using` `System;` `using` `System.Collections.Generic;`   `class` `MainClass {` `    ``// Function to calculate Sum` `    ``static` `void` `EvenOddSum(List<``int``> a, ``int` `n)` `    ``{` `        ``int` `even = 0;` `        ``int` `odd = 0;` `        ``for` `(``int` `i = 0; i < n; i++) {` `            ``// Loop to find even, odd Sum` `            ``if` `((i | 1) == i)` `                ``odd += a[i];` `            ``else` `                ``even += a[i];` `        ``}` `        ``Console.WriteLine(``"Even index positions sum "` `                          ``+ even);` `        ``Console.WriteLine(``"Odd index positions sum "` `+ odd);` `    ``}`   `    ``// Driver Function` `    ``public` `static` `void` `Main(``string``[] args)` `    ``{` `        ``List<``int``> arr = ``new` `List<``int``>{ 1, 2, 3, 4, 5, 6 };` `        ``int` `n = arr.Count;`   `        ``EvenOddSum(arr, n);` `    ``}` `}`

Output

```Even index positions sum  9
Odd index positions sum  12```

Time Complexity: O(length(arr))
Auxiliary Space: 0(1)

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