#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main() {
    cout << "Hello, C++!" << endl;
    
    string name = "Alice";
    int age = 25;
    double pi = 3.14159;
    
    cout << name << " is " << age << " years old" << endl;
    
    auto message = "Modern C++";
    
    // Range-based for
    vector<int> numbers = {1, 2, 3, 4, 5};
    for (auto num : numbers) {
        cout << num << " ";
    }
    cout << endl;
    
    // nullptr
    int* ptr = nullptr;
    if (ptr == nullptr) {
        cout << "Pointer is null" << endl;
    }
    
    return 0;
}