Answered! In the following program, explain what the output will be at Line 1….

explanation :

Here count is initialized as 10 before main function starts to execute.

#include <stdio.h>

#include <sys/types.h>

#include <unistd.h>

int count = 10;

int main(void)

{

pid_t pid;

pid = fork(); ——- (line a)

if (pid == 0) {// child process ———(line b)

count += 15;

return 0;

}

else if (pid > 0) {// parent process ———(line c)

wait(NULL);

printf (“PARENT: count = %dn”, count); /* LINE 1 */

return 0;

}

}

Here, when child process is created successfully at line-a , pid will have process id of child process.

value of pid is 0 in child process and pid stores child process id in parent process.

–> After child process is created, whole parent process is duplicated for child process. So copy of count variable will be different for child process. After child process is created, Any changes made in parent process would not be reflected to child process.

While executing parent process :

for a parent process value of pid is process id of new child, which is a non-zero value.

hence, pid==0 will return false at line-b and pid>=0 will return true.

so default value of count variable will be printed. hence 10 will be printed.

While executing child process :

Child process has count global variable initialized to value 10.

here pid== 0 so condition at line-b will be true for child process and new value of count for child process will be 10+15 = 25. After finishing execution child process exits.

If you have any doubts, you can ask in comment section.