For the block$-$structured C code of Fig. $1\mathrm{.}13($a$),$ indicate the

values assigned to w$,$ x$,$ y$,$ and z$.$

int w$,x,y,z$;

int $i=4$; int $j=5$;

$\{$ int $j=7$;

$i=6$;

$w=i+j$;

$\}$

$x=i+j$;

$\{$ int $i=8$;

$y=i+j$;

$\}$

$z=i+j$;

Figure $1\mathrm{.}13$: Block$-$structured code

$\{$ int w$,x,y,z$; $/*$ Block B$1*/$

$\{$ int $x,z$; $//$

$\{$ int w$,x$; $/*$ Block B$3*/\}$

$\}$

$\{$ int w$,x$; $/*$ Block B$4*/$

$\{$ int $y,z$; $/*$ Block B$5*/\}$

$\}$

$\}$

please show step by step