DataBuffer Fixed Buffer Init

#include <iostream>
using namespace std;

class DataBuffer{
    private:
        int size;   //effective size
        int buffer[20];
        int writeIndex;
    
    public:
        DataBuffer(int s){
            if(s < 1) size = 1;
            else if(s > 20) size = 20;
            else size = s;

            for(int i=0 ; i<20; i++){
                buffer[i] = 0;
            }

            writeIndex = 0;
        }

        void push(int v){
            if(writeIndex < size){
                buffer[writeIndex] = v;
                writeIndex++;
            }

        }

        void print(){
            for(int i=0; i < writeIndex; i++){
                cout << buffer[i];
                if(i < writeIndex-1) cout << " ";
            }
        }
};
int main() {
    int s, n;
    cin >> s >> n;

    DataBuffer buf(s);

    for (int i = 0; i < n; i++) {
        int x;
        cin >> x;
        buf.push(x);
    }

    buf.print();
    return 0;
}