un the following program and identify the pid $($Process ID$)$ of the parent,

child, and grandchild processes. Briefly explain what the program is doing. Run and show

output.

#include

#include

#include

int main$()$

$\{$

pid$\_$t pid, pid$1,$ pid$2,$

pid$0,$pid$3,$pid$4,$pid$5$;

$/*$ fork a child process $*/$

pid $=$ fork$()$;

if $($pid $<0)$

$\{$

$/*$ error occurred $*/$

fprintf$($stderr$,$ "First Fork

Failed"$)$;

return $1$;

$\}$

else if $($pid $==0)$

$\{$

$/*$ child process $*/$

pid$1=$ getppid$()$;

pid$2=$ getpid$()$;

printf$("$Child PID $=$

$\%$d

$",$pid$2)$;

printf$("$Parent PID $=$

$\%$d

$",$pid$1)$;

pid$3=$ fork$()$;

if $($pid$3<0)$

$\{$

fprintf$($stderr$,$Second

fork failed$)$;

return $1$;

$\}$

else if $($pid$3==0)$

$/*$Grandchild process $*/$

$\{$

pid$4=$getpid$()$;

pid$5=$getppid$()$;

printf$("$Grandchild PID $=$

$\%$d

$",$pid$4)$;

printf$("$Child PID $=$

$\%$d

$",$pid$5)$;

$\}$

$\}$

else

$\{$

$/*$ parent process $*/$

pid$1=$ getpid$()$;

pid$0=$ getppid$()$;

printf$("$Parent: $=$

$\%$d

$",$pid$1)$;

printf$("$Root: $=$

$\%$d

$",$pid$0)$;

wait$($NULL$)$;

$\}$

return $0$;