# Find elements of an Array which are Odd and Even using STL in C++

• Difficulty Level : Easy
• Last Updated : 02 May, 2022

Given an array, the task is to find elements which are odd and even, using STL in C++ Examples:

```Input: a[] = {1, 2, 3, 4, 5, 10}
Output: Odd = 3, Even = 3

Input:a[] = {4, 3, 5, 9, 11}
Output: Odd = 4, Even = 1```

Approach: This can be achieved using count_if() method in C++ Syntax:

`count_if(lower_bound, upper_bound, function)`

where, function takes the element of given sequence one by one as a parameter and returns a boolean value on the basis of condition specified in that function. In this case, the function will be:

```bool isOdd(int i)
{
if (i % 2 != 0)
return true;
else
return false;
}```

Below is the implementation of the above approach:

## CPP

 `// C++ simple program to``// find elements which are``// odd and even` `#include ``using` `namespace` `std;` `// Function to check``// if the element is odd or even``bool` `isOdd(``int` `i)``{``    ``if` `(i % 2 != 0)``        ``return` `true``;``    ``else``        ``return` `false``;``}` `// Driver code``int` `main()``{``    ``int` `a[] = { 1, 2, 6, 3, 4, 5 };` `    ``int` `n = ``sizeof``(a) / ``sizeof``(a[0]);` `    ``int` `count = count_if(a, a + n, isOdd);` `    ``cout << "Odd: " << count << endl;``    ``cout << "Even: " << (n - count) << endl;` `    ``return` `0;``}`

Output:

```Odd: 3
Even: 3```
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