C++ question , how can I see the default value of packing

Question

I'm a little confused on the current packing scheme in a struct. Take this example

#include <iostream>

using namespace std;

struct Node
{
    char        c;
    double      d;
    int         s;
} Node;



int main(int argc, const char * argv[]) {
    // insert code here...
    std::cout << "Hello, World!\n";
    cout << sizeof(char) << endl;
    cout << sizeof(double) << endl;
    cout << sizeof(int) << endl;
    cout << sizeof(Node) << endl;
    return 0;
}

This is the output:

Hello, World!
1
8
4
24
Program ended with exit code: 0

I understand that there is a certain scheme of packing. However assuming a size of 8. should this be 1+8 +4 + padding shouldn't it be 16, however its being reported as 24. Is there a way I can find out the default value of packing? I am currently using a xcode on a mac that's not too old.