Question

Write a C program called test that takes one command line argument, an integer N. When we run test:

./test N

the program will do this:

the parent process forks N child processes

each child process prints its process ID, exits

the parent process waits for all child processes to exit, then exits

Answer 1

Hii.. Please check the below ...

Test.c

#include<stdio.h>
int main(int argc, char** argv)
{
  
int n;
sscanf(argv[1], "%d", &n);
for(int i=0;i<n;i++)
{
if(fork() == 0)
{
printf("child[%d] pid %d from [parent] pid %d\n",i,getpid(),getppid());
exit(0);
}
}
for(int i=0;i<n;i++)
wait(NULL);
  
}

Output:
child[1] pid 14452 from [parent] pid 14450
child[0] pid 14451 from [parent] pid 14450
child[2] pid 14453 from [parent] pid 14450
child[3] pid 14454 from [parent] pid 14450

Please check the above and let me know any issues. Thank you. All the best.

Answer 2

#include<stdio.h>
int main()
{

int n;
printf("Please enter the number of child processes: ");
scanf("%d",&n);
// loop will run n times
for(int x=0;x<n;x++)
{

if(fork() == 0)
{

printf("[child] process id %d from [parent] process id %d\n",getpid(),getppid());
exit(0);

}

}

// loop will run n times
for(int i=0;i<n;i++) wait(NULL);

}

OUTPUT:-

UT10. J y ! Thompatible implicit declaration of built-in function exit' main.c:14:13: note: include <stdlib.h>' or provide a declaration of 'exit' main.c:18:5: warning: implicit declaration of function 'wait' [-Wimplicit-function-declaration) Please enter the number of child processes: 6 (child) pid 32327 from [parent] pid 32326 (child) pid 32328 from [parent] pid 32326 (child) pid 32329 from [parent] pid 32326 (child) pid 32330 from [parent] pid 32326 (child) pid 32331 from [parent] pid 32326 (child) pid 32332 from [parent] pid 32326