#include <iostream>

int bar;
class Foo
{
public:
    Foo() : bar(10) {
        std::cout << this->bar << std::endl;
        std::cout << Foo::bar << std::endl;
        
        std::cout << this->foobar << std::endl;
        std::cout << Foo::foobar << std::endl;
    }
    
    static int foobar;
private:
    int bar;
};

int Foo::foobar = 20;

int main() {
    Foo f;
}