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

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 <bits/stdc++.h>
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