DataBuffer Fixed Buffer Init

#include <iostream>
using namespace std;

// Write your DataBuffer class here
class DataBuffer {
private:
    int size;
    int buffer[20];
    int writeIndex;

public:
    DataBuffer(int s) {
        if(s < 1) size = 1;
        else if(s > 20) size = 20;
        else size = s;
        buffer[20] = {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] << " ";
        }
    }
};

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;
}