Initialize Filter3 Class

#include <iostream>
using namespace std;

// Define Filter3 class here
class Filter3{
    private:
        const int id;
        int coeff[3];
        int lastOutput;

    public:
        Filter3(int filterId, int c0, int c1, int c2): id(filterId), coeff{c0,c1,c2}, lastOutput(0){}

        void apply(int x){
            lastOutput = x * coeff[0] + coeff[1] + coeff[2];
        }

        int read(){
            return lastOutput;
        }

};

int main() {
    int id, c0, c1, c2;
    cin >> id >> c0 >> c1 >> c2;

    Filter3 f(id, c0, c1, c2);

    int s1, s2;
    cin >> s1 >> s2;

    f.apply(s1);
    f.apply(s2);

    cout << f.read();
    return 0;
}

Solving Approach