2.

#include <iostream>

int main() {
    int n;
    std::cin >> n;
    int a[n];

    for (int i = 0; i < n; i++) {
        std::cin >> *(a+i);
    }

    for (int* ptr = a; ptr < a + n; ptr += 2) {
        std::cout << *ptr << " ";
    }

    return 0;
}