# Absolute Difference of even and odd indexed elements in an Array

Given an array of integers arr, the task is to find the running absolute difference of elements at even and odd index positions separately.
Note: 0-based indexing is considered for the array. That is the index of the first element in the array is zero.
Examples:

Input: arr[] = {1, 2, 3, 4, 5, 6}
Output: Even Index absolute difference : 3
Odd Index absolute difference : 4
Explanation :
Here, even indexed elements are 1, 3 and 5
So the even absolute difference will be (|1 – 3| = 2) => (|2 – 5| = 3)
Similarly odd indexed elements are 2, 4 and 6
And the odd absolute difference will be (|2 – 4| = 2) => (|2 – 6| = 4)

Input: arr[] = {10, 20, 30, 40, 50, 60, 70}
Output: Even Index absolute difference : 40
Odd Index absolute difference : 40

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: Traverse the array and keep two variables even and odd to store the absolute difference of elements of even and odd indexes respectively. While traversing check if the current index is even, i.e. (i%2) == 0. Print the results in the end.

Below is the implementation of the above approach:

## C++

 `// CPP program to find absolute difference of elements ` `// at even and odd index positions separately ` `#include ` `using` `namespace` `std; ` ` `  `// Function to calculate absolute difference ` `void` `EvenOddAbsoluteDifference(``int` `arr[], ``int` `n) ` `{ ` `    ``int` `even = 0; ` `    ``int` `odd = 0; ` ` `  `    ``for` `(``int` `i = 0; i < n; i++) { ` ` `  `        ``// Loop to find even, odd absolute difference ` `        ``if` `(i % 2 == 0) ` `            ``even = ``abs``(even - arr[i]); ` `        ``else` `            ``odd = ``abs``(odd - arr[i]); ` `    ``} ` ` `  `    ``cout << ``"Even Index absolute difference : "` `<< even; ` `    ``cout << endl; ` `    ``cout << ``"Odd Index absolute difference : "` `<< odd; ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``int` `arr[] = { 1, 2, 3, 4, 5, 6 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr); ` ` `  `    ``EvenOddAbsoluteDifference(arr, n); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to find absolute difference of elements ` `// at even and odd index positions separately ` ` `  `public` `class` `GFG{ ` `     `  `    ``// Function to calculate absolute difference ` `    ``static` `void` `EvenOddAbsoluteDifference(``int` `arr[], ``int` `n) ` `    ``{ ` `        ``int` `even = ``0``; ` `        ``int` `odd = ``0``; ` `     `  `        ``for` `(``int` `i = ``0``; i < n; i++) { ` `     `  `            ``// Loop to find even, odd absolute difference ` `            ``if` `(i % ``2` `== ``0``) ` `                ``even = Math.abs(even - arr[i]); ` `            ``else` `                ``odd = Math.abs(odd - arr[i]); ` `        ``} ` `     `  `        ``System.out.println(``"Even Index absolute difference : "` `+ even); ` `        ``System.out.println(``"Odd Index absolute difference : "` `+ odd); ` `    ``} ` ` `  ` `  `     ``// Driver Code ` `     ``public` `static` `void` `main(String []args){ ` `          `  `              ``int` `arr[] = { ``1``, ``2``, ``3``, ``4``, ``5``, ``6` `}; ` `              ``int` `n = arr.length; ` ` `  `             ``EvenOddAbsoluteDifference(arr, n); ` `     ``} ` `     ``// This code is contributed by ANKITRAI1 ` `} `

## Python3

 `# Python 3 program to find absolute difference of  ` `# elements at even and odd index positions separately ` ` `  `# Function to calculate absolute difference ` `def` `EvenOddAbsoluteDifference(arr, n): ` `    ``even ``=` `0` `    ``odd ``=` `0` ` `  `    ``for` `i ``in` `range``(``0``, n, ``1``): ` `         `  `        ``# Loop to find even, odd absolute  ` `        ``# difference ` `        ``if` `(i ``%` `2` `=``=` `0``): ` `            ``even ``=` `abs``(even ``-` `arr[i]); ` `        ``else``: ` `            ``odd ``=` `abs``(odd ``-` `arr[i]); ` ` `  `    ``print``(``"Even Index absolute difference :"``, even) ` `    ``print``(``"Odd Index absolute difference :"``, odd) ` ` `  `# Driver Code ` `if` `__name__ ``=``=` `'__main__'``: ` `    ``arr ``=` `[``1``, ``2``, ``3``, ``4``, ``5``, ``6``] ` `    ``n ``=` `len``(arr) ` ` `  `    ``EvenOddAbsoluteDifference(arr, n) ` `     `  `# This code is contributed by ` `# Sahil_shelangia `

## C#

 `// C# program to find absolute difference  ` `// of elements at even and odd index  ` `// positions separately  ` `using` `System; ` ` `  `class` `GFG ` `{ ` `// Function to calculate absolute difference  ` `static` `void` `EvenOddAbsoluteDifference(``int` `[]arr,  ` `                                      ``int` `n)  ` `{  ` `    ``int` `even = 0;  ` `    ``int` `odd = 0;  ` ` `  `    ``for` `(``int` `i = 0; i < n; i++)  ` `    ``{  ` ` `  `        ``// Loop to find even, odd  ` `        ``// absolute difference  ` `        ``if` `(i % 2 == 0)  ` `            ``even = Math.Abs(even - arr[i]);  ` `        ``else` `            ``odd = Math.Abs(odd - arr[i]);  ` `    ``}  ` ` `  `    ``Console.WriteLine(``"Even Index absolute "` `+  ` `                      ``"difference : "` `+ even);  ` `    ``Console.WriteLine(``"Odd Index absolute "` `+  ` `                      ``"difference : "` `+ odd);  ` `}  ` ` `  `// Driver Code ` `static` `public` `void` `Main () ` `{ ` `    ``int` `[]arr = { 1, 2, 3, 4, 5, 6 };  ` `    ``int` `n = arr.Length;  ` `    ``EvenOddAbsoluteDifference(arr, n);  ` `}  ` `}  ` ` `  `// This code is contributed by Sachin  `

## PHP

 ` `

Output:

```Even Index absolute difference : 3
Odd Index absolute difference : 4
```

Time complexity : O(n)

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