#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

bool lessThan20Function(int value)
{
    return value < 20;
}

class LessThan20 {
public:
    bool operator() (int value) const
    {
        return value < 20;
    }
};

int main() {

    int iarr[10] = {2,4,55,6,66,10,22,14,70,1234};
    vector<int> v1(iarr, iarr+10);

    LessThan20 lt20;

    // count_if(start_iterator, end_iterator, predicate);

    // Pointer to a function as argument
    int count1 = count_if(v1.begin(), v1.end(), &lessThan20Function);
    cout << "There are " << count1 << " values less than 20" << endl;

    // Function object as argument
    int count2 = count_if(v1.begin(), v1.end(), lt20);
    cout << "There are " << count2 << " values less than 20" << endl;

    return 0;

}