Objects and Classes - General Questions

Static data members are:

What will be the output of the program?

#include <iostream>
using namespace std;
class S {
public:
    static int twice(int v) { return 2 * v; }
};
int main() {
    cout << S::twice(8) << endl;
    return 0;
}

What will be the output of the program?

#include <iostream>
using namespace std;
class Rect {
    int w, h;
public:
    Rect(int a, int b) : w(a), h(b) {}
    int area() const { return w * h; }
};
int main() {
    Rect r(6, 7);
    cout << r.area() << endl;
    return 0;
}

What is the 'this' pointer?

What will be the output of the program?

#include <iostream>
using namespace std;
class A { int a; char c; };
class E {};
int main() {
    cout << (sizeof(E) >= 1) << endl;
    return 0;
}