$```$

$7.$ What do you expect when you run the following code assuming that child PID$=71,$

parent PID$=70?$

#include

#include

#include

#include

static int idata $=100$;

int main$($int argc, char $*$argv$[])$

$\{$

int istack $=200$;

pid$\_$t childPid;

switch $($childPid $=$ fork$())$

$\{$

case $-1$:

printf$("$error: fork

$")$;

exit$(-1)$;

case $0$:

idata$++$;

istack$++$;

break;

default:

sleep$(2)$;

idata $*=2$;

istack $*=2$;

break;

$\}$

printf$("$PID $=\%$ld $\%$s idata $=\%$d istack $=\%$d

$",($long$)$getpid$(),$

$($childPid $==0)?"($child$)"$ : $"($parent$)",$ idata, istack$)$;

exit$($EXIT$\_$SUCCESS$)$;

$\}$

$```$

a$.\backslash (\backslash$quad $\backslash )$ PID $\backslash (=71\backslash )($child$)$ idata $\backslash (=200\backslash )$ istack$=400$

PID$=70($parent$)$ idata$=101$ istack$=201$

b$.\backslash (\backslash$quad $\backslash$mathrm$\{$PID$\}=71\backslash )($child$)$ idata $\backslash (=0\backslash )$ istack $\backslash (=0\backslash )$

PID$=70($parent$)$ idata$=101$ istack$=201$

c$.\backslash (\backslash$quad $\backslash )$ PID$=71($child$)$ idata$=101$ istack$=201$

PID$=70($parent$)$ idata$=200$ istack$=400$

d$.\backslash (\backslash$quad $\backslash$mathrm$\{$PID$\}=71\backslash )($child$)$ idata $\backslash (=0\backslash )$ istack$=0$

PID$=70($parent$)$ idata $\backslash (=200\backslash )$ istack$=400$