C++ References and Pointers

#include <iostream>

int main() {
    int score = 10;
    int* p = &score;     // pointer to score
    int& ref = score;    // reference (alias) to score
    *p += 5;
    ref *= 2;
    std::cout << score << ' ' << *p << ' ' << ref << '\n';
    std::cout << std::boolalpha << (p == &score) << '\n';
    int* nothing = nullptr;
    if (nothing == nullptr) std::cout << "pointer is null\n";
    int arr[] = {10, 20, 30};
    int* first = arr;
    std::cout << *(first + 2) << '\n';
}