std::to_address in C++ with Examples

// C++ code to show
// the use of std::address

#include <iostream>
#include <memory>
using namespace std;

// Allocate memory and return
// the pointer to that memory
template <class A>
auto allocator_new(A& a)
{
    auto p = a.allocate(1);
    try {
        allocator_traits<A>::construct(
            a, to_address(p));
    }
    catch (...) {
        a.deallocate(p, 1);
        throw;
    }

    cout << "Pointer to Memory allocated: "
         << p << endl;
    return p;
}

// Delete memory using
// pointer to that memory
template <class A>
void allocator_delete(
    A& a,
    typename allocator_traits<A>::pointer p)
{
    allocator_traits<A>::destroy(
        a, to_address(p));
    a.deallocate(p, 1);
    cout << "Pointer to Memory deleted: "
         << p << endl;
}

// Driver code
int main()
{
    allocator<int> a;
    auto p = allocator_new(a);
    allocator_delete(a, p);
}

// C++ code to show
// the use of std::address

#include <iostream>
#include <memory>
using namespace std;

int main()
{

    // Make a unique pointer and
    // use to_address to get its address
    // from heap memory
    cout << "Using unique pointers\n\n";
    auto ptr = make_unique<int>(15);
    cout << "Address of pointer to 15: "
         << to_address(ptr) << "\n";

    auto ptr1 = make_unique<int>(17);
    cout << "Address of pointer to 17: "
         << to_address(ptr1) << "\n";

    // Use to_address to get the
    // address of a dumb pointer
    // from stack memory
    cout << "\nUsing dumb pointers\n\n";

    int i = 17;
    cout << "Address of pointer to 17: "
         << to_address(&i) << "\n";

    int j = 18;
    cout << "Address of pointer to 18: "
         << to_address(&j) << "\n";

    return 0;
}