$7-$ Consider the following class declaration:

Class Thing

$\{$

private:

int $x$ :

int $y$ :

static int $z$ :

public:

Thing $()$

$\{\begin{array}{c}x=y=z\end{array}$

static void putThing $($int a$)$

$\{\begin{array}{c}z=a\end{array}$

$\}$;

Assume a program containing the class declaration defines three Thing objects with the following statement: $(10$ min$-20$ points$)$