# Check whether product of ‘n’ numbers is even or odd

Given an array arr[] containing n numbers. The problem is to check whether the product of the given n numbers is even or odd.

Examples:

```Input : arr[] = {2, 4, 3, 5}
Output : Even
Product = 2 * 4 * 3 * 5 = 120

Input : arr[] = {3, 9, 7, 1}
Output : Odd
```

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

A simple solution is to first find the product, then check if the product is even or odd. This solution causes overflow for large arrays.

A better solution is based on following mathematical calculation facts:

1. Product of two even numbers is even.
2. Product of two odd numbers is odd.
3. Product of one even and one odd number is even.

Based on the above facts, if a single even number occurs then the entire product of n numbers will be even else odd.

## C++

 `// C++ implementation to check whether product of ` `// 'n' numbers is even or odd ` `#include ` ` `  `using` `namespace` `std; ` ` `  `// function to check whether product of ` `// 'n' numbers is even or odd ` `bool` `isProductEven(``int` `arr[], ``int` `n) ` `{ ` `    ``for` `(``int` `i = 0; i < n; i++) ` ` `  `        ``// if a single even number is found, then ` `        ``// final product will be an even number ` `        ``if` `((arr[i] & 1) == 0) ` `            ``return` `true``; ` ` `  `    ``// product is an odd number ` `    ``return` `false``; ` `} ` ` `  `// Driver program to test above ` `int` `main() ` `{ ` `    ``int` `arr[] = { 2, 4, 3, 5 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr); ` `    ``if` `(isProductEven(arr, n)) ` `        ``cout << ``"Even"``; ` `    ``else` `        ``cout << ``"Odd"``; ` `    ``return` `0; ` `} `

## Java

 `// Java implementation to check whether product of ` `// 'n' numbers is even or odd ` ` `  `public` `class` `GFG { ` `     `  `    ``// function to check whether product of ` `    ``// 'n' numbers is even or odd ` `    ``static` `boolean` `isProductEven(``int` `arr[], ``int` `n) ` `    ``{ ` `        ``for` `(``int` `i = ``0``; i < n; i++) ` ` `  `            ``// if a single even number is found, then ` `            ``// final product will be an even number ` `            ``if` `((arr[i] & ``1``) == ``0``) ` `                ``return` `true``; ` ` `  `        ``// product is an odd number ` `        ``return` `false``; ` `    ``} ` ` `  ` `  `    ``// Driver code ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `            ``int` `arr[] = { ``2``, ``4``, ``3``, ``5` `}; ` `            ``int` `n = arr.length ; ` `            ``if` `(isProductEven(arr, n)) ` `                ``System.out.println(``"Even"``); ` `            ``else` `                ``System.out.println(``"Odd"``) ;       ` `    ``} ` `    ``// This Code is contributed by ANKITRAI1 ` `} `

## Python3

 `# Python3 implementation to  ` `# check whether product of 'n'  ` `# numbers is even or odd ` ` `  `# function to check whether  ` `# product of 'n' numbers is  ` `# even or odd ` `def` `isProductEven(arr, n): ` ` `  `    ``for` `i ``in` `range``(``0``, n): ` ` `  `        ``# if a single even number is  ` `        ``# found, then final product  ` `        ``# will be an even number ` `        ``if` `((arr[i] & ``1``) ``=``=` `0``): ` `            ``return` `True` ` `  `    ``# product is an odd number ` `    ``return` `False` ` `  `# Driver Code ` `arr ``=` `[ ``2``, ``4``, ``3``, ``5` `] ` `n ``=` `len``(arr) ` `if` `(isProductEven(arr, n)): ` `    ``print``(``"Even"``)  ` `else``: ` `    ``print``(``"Odd"``)  ` ` `  `# This code is contributed  ` `# by ihritik `

## C#

 `// C# implementation to check  ` `// whether product of 'n'  ` `// numbers is even or odd ` `using` `System; ` ` `  `class` `GFG  ` `{ ` `     `  `// function to check whether  ` `// product of 'n' numbers ` `// is even or odd ` `static` `bool` `isProductEven(``int` `[]arr, ``int` `n) ` `{ ` `    ``for` `(``int` `i = 0; i < n; i++) ` ` `  `        ``// if a single even number is  ` `        ``// found, then final product  ` `        ``// will be an even number ` `        ``if` `((arr[i] & 1) == 0) ` `            ``return` `true``; ` ` `  `    ``// product is an odd number ` `    ``return` `false``; ` `} ` ` `  `// Driver code ` `public` `static` `void` `Main() ` `{ ` `    ``int` `[]arr = { 2, 4, 3, 5 }; ` `    ``int` `n = arr.Length; ` `    ``if` `(isProductEven(arr, n)) ` `        ``Console.WriteLine(``"Even"``); ` `    ``else` `        ``Console.WriteLine(``"Odd"``) ;  ` `} ` `} ` ` `  `// This code is contributed by ihritik `

## PHP

 ` `

Output:

```Even
```

Time Complexity: O(n).

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