#include <iostream>

// A constexpr function to calculate the product of two integers
constexpr int product(int x, int y)
{
    return x * y;
}

int main()
{
    // Calling product with constant arguments, allowing compile-time evaluation
    constexpr int compileTimeResult = product(5, 7);
    cout << "Compile-time result: " << compileTimeResult << endl; // Output: 35

    // Using the constexpr function to define the size of a C-style array
    int arr[product(2, 3)]; // Size of arr is 6, determined at compile time

    // Initialize and print elements of the array
    for (int i = 0; i < product(2, 3); ++i) {
        arr[i] = i + 1;
        cout << arr[i] << " ";
    }
    cout << endl; // Output: 1 2 3 4 5 6

    // Calling product with a runtime argument, forcing runtime evaluation
    int a = 10;
    int runtimeResult = product(a, 4); // Evaluated at runtime
    cout << "Runtime result: " << runtimeResult << endl; // Output: 40

    return 0;
}