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 12Explanation: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 = 12Input :arr = {10, 20, 30, 40, 50, 60, 70}Output :Even index positions sum 160 Odd index positions sum 170Explanation: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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